On December 10, 2003, a gunman opened fire as a family of four entered their home, killing two and wounding the others. He’d pulled open a few drawers to make it look like a robbery, but the scene was clearly staged. When police pieced together the clues, they discovered an unlikely suspect and a carefully orchestrated plot.

A drive-by shooting leaves one man dead and another seriously wounded. Cell phone calls and shell casings point to a suspect, but authorities are unable to place him at the crime scene. When a forensic geologist compared soil from the crime scene with soil found in the wheel wells of the suspect's car, he proved that dirt is anything but dumb.

When court clerk Peter Porco doesn't report to his work in November 2004, a courts officer is ordered to the Porcos' family home in Bethlehem, NY. Inside the home, he finds murdered Peter Porco and his barely alive wife Joan who had both been savagely attacked with a fireman's axe. Eventually, a DNA sample may lead to the killer.

Terrified, the young girl hid in her bedroom while her mother, Crystal Perry, was attacked and stabbed to death in her home in Bridgton, ME, on May 12, 1994. Investigators had a wealth of evidence: shoe impressions, distinctive blood drops, and the killer’s DNA. What they didn’t have was a basis for comparison.

Georgia resident Sheila Bryan, who was convicted of killing her mother in a car fire, is granted a new trial. An expert fire witness shares an opinion on how the fire ignited which differs from the prosecution's theory and, if verified, would clear Bryan of any culpability. [also marked as S7:E50]

When two women from the same town were murdered in the same way, police feared a serial killer was on the loose. At first they thought the victims had nothing in common until they found tiny clues linking them to the same man.

It's usually easy to determine how a criminal entered the crime scene. But in this case, it was far from clear. It looked like the killer vanished into thin air...and perhaps he had.

Respected surgeon Brian Stidham was stabbed to death in the parking lot next to his office. The most likely suspect is seen having dinner in a restaurant at the time of the murder. But a cryptic conversation leads police to believe that, while the suspect may not have wielded the knife, he could very well have hired the man who did.

In April 2002, a wild fire in a secluded parking lot leads police to discover the dreadful homicide of David Nixon, with the suspect's image caught by security cameras.

There was no clear reason for a young, healthy college student to be dead. But when the medical examiner discovered the tiniest of clues during the autopsy, investigators were able to uncover the mystery filled with betrayal and revenge.

In 1992, in a rural Canadian community, Dr. John Schneeberger is accused of sedating and sexually assaulting two of his female patients. DNA tests show him to be innocent, but the women persist with their claims; 7 years later, a private investigation leads to a surprising discovery.

Seattle police had no suspects in the violent murder of post-grunge singer, Mia Zapata. More than a decade would pass before the evidence collected by an extraordinarily prescient medical examiner could be used by forensic scientists to identify the killer.

In 1994, a human skull found in an Ohio pond uncovers a ghastly crime. Markings on the skull indicate that the victim had been stabbed many times and that the teeth had been removed with needle-nose pliers in an attempt to keep the victim's identity a secret. Forensic scientists use DNA matches to indentify the skull.

It was classic “overkill.” Barbara Mullenix, found floating in the harbor of an upscale yacht club in Newport Bay on September 13, 2006, had been stabbed more than 50 times. Her ex-husband and daughter are missing, and investigators turn to forensic science to determine if they’re searching for victims... or perpetrators.

A woman disappears without a trace; even though foul play is suspected, the leads don't pan out and the trail turns cold. Twenty years would pass before police are able to link a clump of hair discovered in an isolated area with the missing woman. Members of "NecroSearch," a group of volunteer forensic scientists, searched a remote area of Colorado a meter at a time, found the victim's body, and gave authorities the evidence they needed to bring the killer to justice. [also marked as S9:E5]

A man is found dead in his home, and his ex-wife has a perfect alibi. To determine time of death, investigators need to know when the victim ate his last meal. An endocrinologist, a forensic botanist, and a short-order cook answer their question.

When a woman disappeared without a trace, there were two possible explanations: kidnapping or murder. Concern was heightened when police learned that two other women had vanished under similar circumstances. Careful investigation, the talents of a forensic artist, and DNA profiling enabled police to link the crimes to a single suspect – an immigrant known to prey upon vulnerable women. [also marked as S9:E25]

In 1984, California firefighters had battled ten arson fires in three weeks. When cigarettes and a scrap of paper connected the southern California fires to several fires further north, the hunt was on for a dangerous pyromaniac. Investigators finally found a fingerprint, and it pointed to a most unlikely suspect.

At a murder scene, investigators find a shoe-print, several foreign hairs, and unknown fingerprints. But they believe the most telling piece of evidence is the bite mark on the victim's chest.

An Alaskan police officer found a woman's body while on routine patrol of a public park. The victim had been stabbed to death and, during the autopsy, the medical examiner preserved the portion of her rib cage which sustained the fatal wound. A knife thought to be the murder weapon turned up days later, two thousand miles away. Forensic scientists now had an opportunity, which seldom occurs, to compare the microscopic marks on the presumed murder weapon with the marks on the victim's bone.

A behavioral profile is helpful in a murder investigation, but it's not a road map to the killer. One such profile caused the Baton Rouge Police Department to search for the wrong man. They might not have made an arrest, had it not been for a DNA picture of the suspect, painted by a molecular biologist. [also marked as S10:E15]

How unlucky could one man be? His wife had taken her own life, and his college sweetheart had killed herself in much the same fashion fourteen years earlier. Investigators had to determine if this was a bizarre coincidence, or an attempt to get away with murder... twice.

When an 11-year-old girl disappeared from a small town in a remote area of Alaska, investigators wondered if she'd been attacked by a bear or become lost in the dense woods. It turned out neither was true.

A young woman attends evening church services... then disappears. When her abandoned car is found, the tank is empty and a gas can she kept in her trunk for emergencies is missing. Eyewitnesses place her at a nearby gas station, getting into a van, but their descriptions of the vehicle don't match. Three days later when her body is discovered, the search for the driver of that van intensifies.

An assistant manager of a Florida steakhouse is stabbed to death. It appears to be a robbery gone wrong, but a bloody fingerprint reveals that he knew his killer.

Time of death becomes pivotal after a pregnant woman is found murdered in her air-conditioned bedroom. A striking similarity between her death and an HBO movie gives examiners the clues they need to thaw out the alibi of a cold-blooded killer.

In 1991, Maine resident Pearl Smith is missing after an argument with her husband, Bill Bruns. Despite pleas from her children, police treat it as a routine missing person's case. But, when an investigation turns up a blood trail that leads to the couple's basement, police are certain they'll finally find the victim's body.

The victim had been stabbed more than a hundred times, leaving her bedroom soaked with blood. Even though her body was positioned in a suggestive way, she hadn't been sexually attacked. Was this a sex crime, or was it a random act of violence?

In 1987, the death of Crystal Purcell was considered an accident. Then in 2001, Barbara Purcell called police to suggest that her estranged husband Willard had killed Crystal, who was her husband at the time of her death. Before that investigation could begin, Barbara was found dead in much the same manner as Crystal. Was this an unfortunate coincidence or the M.O. of a serial killer?

A 29-year-old woman was killed instantly when a bomb exploded in her home. The device was so powerful that shrapnel was embedded in houses across the street. The bomber had not only knowledge and skill, but also a motive for murder.

The driver said he couldn't have hit and killed a pedestrian on a Harrisburg street. The Jeep Grand Cherokee he was leasing around that time had been sold months ago to a buyer in another state. Police were able to find the vehicle. They impounded it, took it apart, and discovered evidence, which would tell them what really happened that night.

When a decomposed body is discovered inside a barrel, police immediately suspect foul play. But the body had been placed there 30 years earlier. One of the few clues was an address book found along with the body but years of moisture had washed away the ink. Scientists desperately searched for a way to unlock the secrets of that address book.

In 2007, Brian & Beverly Mauck were found dead in their Graham, WA home. The killer obviously spent a great deal of time at the scene, wiping away his fingerprints and obscuring shoe impressions he’d tracked through blood trails on the floor. But in the process, he created new evidence which was just as incriminating.

Details the case of the Beltway sniper attacks, a 3-week shooting spree which left 10 people dead in the Washington, D.C. area.

When a college co-ed vanished without a trace, her fellow students were concerned about her safety and their own. Weeks later, the body of an unknown female was discovered 700 miles away in the ashes of a barn fire, and an alert police officer realized the two crimes might be connected.

Whoever stabbed a young Texas mother to death had also savagely beaten her 4-year-old daughter. Police had a suspect, but not enough evidence to tie him to the crimes. It would take 15 years and advances in DNA technology to bring the killer to justice.

In a tragic twist of fate, just days after the woman sold her home and moved to a modest trailer, a fire took both the trailer and her life. But the autopsy proved this was no accident. It was arson and murder. Investigators had to determine who wanted the woman dead... and why.

A World War II veteran was found dead in his home, and the investigation ground to a halt when the prime suspect had a solid an alibi. But a lucky break led to a shady character who wore distinctive boots and had a sweet tooth.

Hikers near Anchorage, Alaska discovered a body wrapped in sheets edged in orange stitching. Authorities hydrated the fingers and obtained a fingerprint, enabling them to identify the victim. Clinging to the sheet, they also discovered a tuft of red carpet fibers – threads of evidence, which led them straight to the killer. [also marked as S9:E30]

The body of a young California co-ed was found under an isolated ramp of the Interstate, and San Diego police had no idea who would want this girl dead. But their questions would be answered when they discovered a tiny, unique fiber on the victim's clothing, which led them straight to the most unlikely of killers.

A teenager went missing after an evening of horseback riding. Her body was found a month later, three miles from her home. The killer unknowingly left trace evidence behind – tiny but unmistakable clues which pointed to him and him alone.

When the head chef of a historic Philadelphia restaurant was found dead, investigators interviewed the usual suspects: family, friends and coworkers. As they sifted through the evidence, police uncovered a chilling tale of debt and deceit.

A Michigan State University grad student disappeared and was presumed dead. With the help of a professor of geological sciences, police hoped to get the "dirt" on her killer.

The prime suspect had a criminal record, and his driver's license was found at the scene of a brutal, double homicide. That physical evidence seemed damning, but it wasn't the only evidence. DNA extracted from a discarded spoon would point investigators in a different direction.

Now it's not only a fingerprint which can link a killer to a crime; a shoe print can be just as telling. Armed with little else, police hoped the shoe impressions found at a Lansing, MI crime scene would put their investigation of Audrey Nichols' murder back on track.

In 1993, young mother Tammy Tatum was found sexually assaulted and murdered in her Longmont, CO apartment. Police initially suspect her estranged husband, but did not have enough evidence to charge him and the case went cold. Three years later, another young woman was raped and police suspect the cases may be related. Despite meticulous washing of the crime scene, a single hair remains to lead authorities to the culprit.

A 6-year-old girl ran and hid when she saw her grandmother being beaten to death, but the man followed her, beat her and assaulted her. The girl said he was her Uncle Clarence, and he was convicted because of her identification. She recanted her testimony years later, but the court denied Clarence's petition for a new trial. His wife was convinced he was innocent, and decided to conduct her own investigation to prove it.

Lori Keidel, her two sisters and her brother were left home alone while their father went to a nearby laundromat. Suddenly, a large fire engulfed their brick ranch home. Only a few months earlier, the children's mother had disappeared and made no effort to contact them. Lori found the courage to tell police that she had witnessed her own mother's death.

In 1998, a convience store clerk in Lansing, Michigan, was shot to death during a robbery. No one else was in the store at the time. But there was an eye witness, a security camera. Unfortunately, the story it told was far from clear.

In 1991, when the wife of a serviceman was brutally murdered in the Philippines, the Air Force Office of Special Investigators swung into action. Clues led to the victim's husband, but he insisted he was innocent. To find out if he was telling the truth, investigators would have to do something unprecedented: Reassemble a 5-1/4 inch computer disk which had been cut to pieces with pinking shears.

A bullet-riddled car, a missing driver, and no witnesses. Was this an ambush or a random attack? Had the victim been abducted or was she dead? The answers lay in a unique clue so tiny it was measured in millionths of a meter.

As she left choir practice, a woman was gunned down in the church parking lot. Her husband became the prime suspect – particularly when police learned he found out just a month earlier that his wife had been cheating on him for three years.

Three homicides on two continents looked like professional executions. Investigators on both sides of the Atlantic needed to find out if they were related and, if they were, who or what they had in common.

It was one of the most unusual cases in forensic history. Investigators had to find a way to solve a murder case with evidence which consisted of a squashed tomato found at the crime scene, and tiny, pinpoint reflections of light in a photograph. Would it be enough to catch a killer?

Forensic scientists work with the only clue recovered from a multiple-victim shooting: a 12-gauge shotgun. Scientists use unique methods to lift the serial number from the weapon in order to trace it to its owner. [also marked as S7:E40]

In 1980, Michigan resident Shannon Mohr died tragically in what was reported by her new husband, David Davis, as a horseback riding accident. Upon deeper investigation, police uncover a thread of lies in Davis' background after his suspicious behavior prompts a closer look.

In 2005, David Castor suffered a slow, agonizing death over a period of days. His wife Stacey maintained it was suicide, even though it was done with antifreeze. Police were skeptical, especially when they learned Stacey's first husband Michael Wallace died when he was only 38 years old and she refused to consent to an autopsy.

The 1991 disappearance of Newport Beach, CA, resident Denise Huber stumps investigators. Three years later, Arizona residents call police to report John Famalaro, who has kept a Ryder rental truck in his driveway, which they suspect is stolen. Upon further investigation, police find a body within a freezer inside the truck, which they conclude is Denise Huber.

The crime scene was especially violent: A husband and wife had been shot to death in their bedroom. At first, investigators thought their 16-year-old daughter was lucky to have escaped unharmed... but after a while, they wondered if the reason she was alive had more to do with careful planning than good fortune.

A woman is shot to death in her store just one day before she is to testify against the man accused of robbing her. The robber becomes the prime suspect, but he has a solid alibi: a time-stamped videotape of his activities on the day of the murder.

The news of a flight attendant's brutal murder prompted the son of a victim who had been killed five years earlier to contact police. The M.O. of both murders was remarkably similar, and analysis of the biological evidence from the crime scenes proved that these were serial killings.

A 19-year-old woman was found dead in her car; the scene had been staged to appear to be suicide. During their investigation, police discovered the victim was involved in a love quadrangle, giving several people motive to kill. The killer's identity would be revealed by a piece of evidence found in a suspect's trash. [also marked as S9:E18]

A 34-year-old nurse experiences a variety of flu-like symptoms. None of her doctors are able to discover the cause, until she visits the gynecologist for a routine check-up. Then she learns it's something far worse than the flu.

The woman had been sexually assaulted, stabbed repeatedly, and left for dead. She survived, and gave police a detailed description of her attacker. When someone who fit that description practically turned himself in, police were sure they had their man... until the DNA evidence proved them wrong.

The body of an attractive young woman was found a mile from her abandoned car. Police were especially concerned when they realised the victim had come to them for protection just two weeks earlier, after a road rage incident. Concern turned to dread when the evidence began to point not to an aggressive driver, but to one of their fellow police officers.

In 1991, Dorothy Donovan was murdered in her Dover, DE home and police are skeptical when her son Charles Holden stated that she was murdered by a hitchhiker he had picked up. Their suspicions were heightened when he refused to take a polygraph test and they turned to forensic science. Would the blood and fingerprint evidence at the crime scene support Charles' story or prove his guilt?

A possible case of Munchhausen syndrome is investigated after an infant dies of what appears to be toxic levels of antifreeze in his system.

In 1971, John List left a note with the bodies of his mother, wife, and three children in his mansion ballroom, funeral organ music blaring from a central sound system, and disappeared. Eighteen years later, all detectives had to work from is an outdated photograph of List. In 1989, the popular television series America's Most Wanted commissioned an age-scaled bust of List to aid viewers in identifying the confessed murderer. Dr. Frank Bender, nationally-recognized artist and sculptor, worked with forensic psychologist Richard Walter to develop a profile of the aging List.

A man died in his home after a long history of heart disease. It was assumed that this was the cause of his death. A few weeks after the funeral, rumors surfaced that the death was no accident.

In 1981, Charlotte Grabbe, the estranged wife of prominent Illinois farmer Fred Grabbe, disappeared from her farm without a trace. His former lover comes forward with an outlandish tale of rage, murder, mutilation and cremation. The tests of a plant pathologist and a dendrochronologist lead to a surprising revelation.

A woman is found dead in a ravine, but crucial crime scene evidence had been washed away by severe thunderstorms. Twice, the trail turned cold. Almost 20 years later, an old hat and a chip of stainless steel brought the killer to justice.

In 2000, Judy Southern arrived home from work and was shot by a gunman waiting within. Her husband Allen arrived shortly afterwards, called 911 to report his wife had been shot and drove her to the hospital. She died on arrival and the investigation focused on her husband Allen, but forensic analysis and a suicide note found at the scene pointed to the killer.

In 1984, the body of college co-ed Laura Salmon was found on a Georgia farm, covered with her own denim jeans as well as the jeans of the killer. Investigators had plenty of suspects, including former boyfriend David Kyle Gilley, but no conclusive evidence linking any of them to the crime. More than a decade later, sophisticated technology would breathe new life into a case grown cold with the passage of time and implicate her killer.

When a dedicated, well-respected teacher disappeared, police had to determine if she'd gone on vacation without telling anyone, or if she was the victim of foul play. Investigators turned to forensic science, hoping to find the answers they needed.

For 15 months, a serial killer in Tampa, FL, taunts police by strangling prostitutes and leaving their bodies in plain sight, but tire marks and fibers lead to the culprit.

A young mother is murdered after years of domestic abuse. There are clues at the scene: bloody footprints and DNA from the victim’s rape kit.

A serial bomber was on the loose in Illinois. Two churches had been bombed and one person was killed. Investigators had to capture the criminal before he struck again and they hoped to catch him by following a thin copper wire.

The victim was well liked and successful, which made the brutality of the crime even harder to understand. In the final moments of her life, she'd written a name on the wall, presumably that of the killer – in her own blood. But this wasn't an open and shut case and, in order to solve it, investigators would have to read between the lines.

Two men were murdered, while sleeping in their bed. One night later, an arson fire destroyed a family planning clinic. Investigators wondered, wherether some shards of glass, paintchips and a chicken feather, could link for what appeared to be, two separate crimes.

In 1995, police in San Diego, CA, are baffled by a pair of hands found in a dumpster. Through further investigation, they determine that the hands are those of missing person Don Hardin. With this knowledge, the police focus on local homeless man Dale Whitmer, whom had lived with Hardin around the time of his disappearance. However, they can find no solid, forensic evidence on Whitmer and the case goes cold. About a year later, investigators receive an anonymous letter with information about the crime that had been withheld from the press – information only the killer (or someone close to the killer) would know. Laser technology helps to identify the state, city, street address and even the office number from where the anonymous letter was mailed.

A 13-year-old girl went missing from her Colorado home, and the only evidence the kidnapper left behind was three fingerprints on a window screen. Two years later, a latent print examiner, new to the county and the crime lab, changed the course of the investigation by sharing a little-known fact with his colleagues.

Joshua Ford and Martha Crutchley spent Memorial Day weekend at the beach, and then they simply vanished. A week later, police would get an unexpected lead from a robbery in progress, and the evidence they found helped solve a crime of unparalleled violence and brutality.

Lives changed in the 20 years following an unsolved murder, and so did forensic science. In time, a high-powered microscope and DNA profiling revealed not only a clue no one had seen before but also the identity of the killer.

The first case to use DNA evidence is detailed. In 1983 Leicester, England, police were stymied by a rape/murder of a 15-year-old girl; three years later, faced with a similar crime, they turned to Dr. Alec Jeffreys, a molecular biologist with a revolutionary approach to solving the case.

In 1996, Shannon Sanderson goes the casino without her husband Robert and wins $5,000 at the Blackjack tables. Three hours later, she is abducted by a man driving a Chevy Beretta and a month later, she was found dead. The trail turned cold, until police got a call from a woman who suspected her husband, who had a criminal past.

A two-man shrimp boat sank when a fast-moving, violent storm struck the Louisiana coast. The captain drowned, and the deckhand was rescued fourteen hours later. He told the Coast Guard that the captain's foot had become entangled in the fishing nets; they tried frantically to free him, but they failed. The deckhand was considered a hero until the captain's body was found. Eventually, the public discovers that he was coerced into confessing to the captain's murder.

In 1985, Julie Estes, then 21, was abducted from her late-night job at the Southside convenience store. Her body was found the next day, she had been raped and strangled. Her murder went unsolved until 2003 when it was reopened by the new cold case squad at the Jacksonville Sheriff's Office, who look to DNA evidence to try to nail the killer.

In 2008, Illinois emergency response came upon a garage fire and a man was found crushed beneath a truck. Upon first glance, the victim was the homeowner Ari Squire. Investigators turned to forensic science to determine if they were dealing with a tragic accident or a carefully orchestrated murder.

A vibrant young woman falls to her death from a cliff overlooking the Pacific Ocean In what appears to be a tragic accident; a forensic examination of photographs taken at the scene tell a different story. [also marked as S9:E14]

Creating a “profile” of a serial killer is part science and part intuition. The science involves studying criminals who have committed similar crimes, to see what characteristics they have in common. In a search for the killer of two teenagers in Texas, a behavioral profile led to a possible suspect - and hard science proved the profile was correct; it shows a behavioral study on how most serial killers also have a history of abusing animals.

In 1989, 4-year-old April Loveless was found dead in the backyard of her Texas home. Her mother Debbie Loveless and step-father John Miller told police that she was attacked and killed by neighborhood dogs, but the injuries on her body didn't match their account of what happened. Investigators believed April's wounds were slashing injuries, consistent with a knife wound. John and Debbie were found guilty of murder and sentenced to life in prison. Five years later, the parent's prayers were answered when a forensic scientist saw something in the crime scene photographs that had been missed the first time around.

In 1995, California model Linda Sobek goes missing. A park employee discovers photographs and some vital pieces of information in a dumpster, which eventually led investigators to professional photographer Charles Rathbun. Rathbun claims Sobek died during a consensual sexual encounter gone wrong, but Sobek's corpse and some high tech digital imagery tell a more sinister story.

Bombings are difficult to solve, because the perpetrator isn't usually at the scene, and the evidence goes up in smoke. But there are clues if investigators know where to look. In this case pieces of plastic the size of grains of sand, held the key to a man's murder.

After a street fight took the life of a national wrestling champion, police had to determine if he was killed in cold blood, or in self-defense. A jury decided it was murder, and sentenced the accused to a minimum of twenty years in prison. Six years later, he was granted another trial; a forensic animator, who testified on his behalf, offered a different explanation for the most damning piece of evidence. [also marked as S9:E17]

In the spring of 1993, an unexplained illness struck the residents of Milwaukee, Wisconsin. Four hundred thousand people developed a serious gastrointestinal illness, 4,000 were hospitalized and, by the time the epidemic was under control, more than 100 people were dead. Health officials suspected it was influenza, but it proved to be more serious and more difficult to identify.

In 1991, Grand Junction, Colorado is on edge after a series of deadly bombings which has killed 2 and injured one more and police race to find the culprit before he strikes again. Ultimately, it was the bombs themselves, along with the tools used to make them, which led investigators to the perpetrator.

For seven years, a trio of men robbed one bank after another leaving no evidence behind. But forensic scientists help catch them by looking at the criminals' posture and clothing. [also marked as S9:E9]

In Dripping Springs, TX, March 1999, a 3-year-old boy develops serious respiratory problems and then his father later shows signs of early Alzheimer's disease. A chance encounter with a stranger kicks off an investigation into the cause. [also marked as S7:E19]

In 1994, 67-year-old grandmother Rhoda Nathan was found murdered in a Cincinnati hotel room. When a patient in a hospital emergency room said he cut his hand on a dumpster, the doctor treating the injury recognizes it as something else -- and soon because the chief witness and a murder case.

In 2008, Colorado real estate developer Alan Helmick was found shot to death at home. His wife Miriam became the prime suspect. Police had a wealth of evidence against her, but it is circumstantial. The case will turn on a .25 caliber bullet fired 20 years ago from the now-missing murder weapon.

In 1993, 16-year-old Marie Robards suffered the devastating loss of her father Steve Robards. The death was ruled the result of cardiac arrest. One year later, she won a part in her high school production of Shakespeare's Hamlet. The lines she was required to recite onstage were more than the thoughts and feelings of her character; they struck a chord, and hinted at her own inner turmoil, from the secret she had been hiding.

In 2003, Rebecca Barney and her soon-to-be ex-husband Fred were found shot to death in their Tulsa, OK, home, which had been set on fire. After the fire was extinguished, Kenneth Maxwell, who was the man who had called 911 to report the fire, was also found shot dead in his car. Only the computer had been taken from the Barney home and with it, seemingly the means to identify the killer.

Detectives think they've solved a murder when they find the weapon and victim's blood in a man's flat, but the evidence may have been planted.

For years, a woman suffered from what appeared to be the unpleasant side effects of lithium, a drug prescribed to treat bipolar disorder. When she died, investigators had to determine if her death was due to natural causes, suicide, or murder.

When Firefighters found an entire family dead, inside their home, it looked like a murder-suicide, but there were several inconsistent clues in the rubble. Could ballistics, a time card, and some secret audiotapes unravel the mystery?

In 1969, 25-year-old phone operator Diane Maxwell is raped and murdered by a black man. Her brother promised he'd find out who was responsible and bring the killer to justice. It would take more than thirty years, but the young man kept his promise and, in doing so, brought closure to his family.

A mysterious computer crash pushed a thriving manufacturing company to the brink of collapse, jeopardizing the jobs of hundreds of employees. There was no apparent cause; there were no obvious clues. Forensic investigators had to determine if the crash was the result of a computer defect, human error, or sabotage. [also shown as S10:E14]

A Native American woman was brutally killed in the desert of New Mexico, and the crime scene was rich in forensic evidence: tyre tracks, shoe impressions and even the murder weapons. The site was less than 10 miles from another crime scene where, two years earlier, a male Native American was beaten and stabbed to death. Police began to wonder: was a serial killer on the loose?

In 2003, Kathy Lorick was raped and murdered on a Concord, California jogging trail in the middle of the day while talking to her husband on her mobile phone. The leads from Kathy's cell phone records and search dogs go nowhere. Nine days later, a witness tells police about a chance encounter.

In the early hours of a morning just before Christmas, a college co-ed was abducted from the parking lot of her apartment. Her body was found later that day; she'd been sexually assaulted and then shot at point blank range. Eight long years passed and then a pair of running shoes and a cell phone breathed new life into a very cold case.

In 1999, a 12-year-old was found murdered in her home and it changed the feeling of security residents had in the small town of Waseca, Minnesota. Despite a meticulous search of the home and an exhaustive investigation, police had no suspects.

In 1996, 54-year-old Gayle Isleib was ambushed in her Manchester, Connecticut driveway and shot to death. During their investigation, police learned that her 25-year-old co-worker Tyrone Montgomery was in love with her and that she had spurned his advances. They now had to determine if love had turned into obsession... and a motive for murder.

A house erupted in flames on a cold January night, killing one person and injuring another. The survivor blamed a kerosene heater but the evidence at the scene did not support her story, and she was charged with arson and murder. It would take a nationally known fire investigator to determine what happened, and who was responsible.

When a popular disc jockey was found murdered in a community garden, police swung into action. A sniffer dog and a blood spatter expert led police to the killer and he'd been much closer than they realized.

The shooting of a man during a hunting trip is reopened years after the incident, and the victim's hunting partner becomes a suspect.

Foul play is suspected when Fort Worth factory worker Glenda Furch disappears in September 2007 after completing her shift. Evidence suggested she had been bound, sexually assaulted and murdered. Afterwards, the killer spent hours at the crime scene, wiping away his fingerprints and disposing of everything which might incriminate him, including her body. Police now face a daunting task: They not only have to find the killer, they also have to find the body of the victim.

In 1957, California police searched for a man who had committed several crimes in one night – including murder, but after following thousands of leads, eventually, the case turns cold. Almost 50 years later, with advances in computer technology and handwriting analysis, investigators determine the killer.

A young girl is found dead, the victim of an apparent sex-killer. Authorities are intrigued by unusual orange fibers embedded in clothing found near the victim. Months pass and the case goes cold, until a van turns up with what appear to be the same orange fibers.

A serial bomber was waging a vendetta against the legal profession: a judge, two attorneys, and even a courthouse had been targeted. Employing a range of forensic techniques, investigators used evidence from the bombs to lead them to the perpetrator.

The victim has been stabbed more than thirty times, and the crime scene is awash with her blood. Near her head, police discover a distinctive button with strands of thread still attached. If they can find the owner of the shirt the button came from, they'll also find the killer.

In 1993, 82-year-old Kathryn Bishop was found dead in her Pennsylvania home. The evidence at the scene indicated that the perpetrator had been running out of the house, not breaking into it. Tiny clues on the victim's body would tell police what happened that night, and who was responsible.

When a hit-and-run boating accident caused the death of a popular young man, investigators faced the daunting task of searching for one boat among 1200 others. They asked anyone who had seen the accident to come forward. The man who responded did much more than witness the crash; he was a passenger in that other boat.

A sixteen-year-old girl is killed in her own home by her mother and father. Her parents said they acted in self-defense, but the forensic evidence indicates otherwise. Definitive proof would come from an unlikely source: a recording made by an FBI electronic surveillance device. [also marked as S8:E28]

In 1997, Kelly Eckart's car was found with her belongings still in it, after working the late shift in Franklin, Indiana. Days later, her body was found in an isolated ravine. Tiny clues told police a great deal about the killer: he would own a car with olive-colored carpeting, a white blanket and distinctive bullets made from wax, not lead.

In 1994, on Canada's Prince Edward Island, the body of Douglas Beamish's estranged wife, Shirley Duguay, was discovered. In a groundbreaking case using animal dna, investigators use forensic testing on a cat to help them solve the case.

The woman could have lost control of her SUV on the icy road, and plunged down an embankment into a shallow creek. But there were footprints in the snow leading away.

The crime scene was awash with blood. The victim had been brutally murdered as he slept in his own bed. There were no foreign fingerprints in his home, but investigators did find a shoe impression in the mud outside physical evidence they hoped would lead them to the killer.

The body of a wealthy American businessman was found in his rental car. Teeth and bone fragments were the only remains. When the victim's wife files an insurance claim for $7 million, investigators seek the help of a renowned forensic anthropologist.

An employee of a dry cleaner was raped and murdered in the store, and investigators thought themselves fortunate to have two eyewitnesses. Their descriptions were similar but not identical, and the prime suspect didn't come close to resembling that person. Police turned to forensic science for the answers they needed.

A look back at a trio of unsolved murders that occurred in Wichita Falls, Texas during the 1980s, details how a fourth murder from the same time period provided the police with more than they realized. John Little, an investigator for the DA's office, picked up the cold cases years later and made a connection to the other murders.

In 2006, Jackson, MS, resident Avis Banks and her unborn child were brutally murdered in her garage and discovered by her fiancé Keyon Pittman. Police learn Pittman was having affairs with other women and he became the prime suspect... that is until a man comes forward who not only believes he owns the murder weapon, he also knows who used it.

In 1981, New York correctional officer Donna Payant disappeared and her body was later found in a landfill; investigators suspect the prisoners in the facility where she worked. The medical examiner uses a "signature" clue to link her death to a murder the same examiner investigated 10 years earlier.

A woman is found dead from a gunshot wound and police suspect her husband; however, forensic teams prove what really happened and the truth is stranger than fiction. [also marked as S7:E17]

Between 1986 and 1989, a disease swept through British cattle herds, which came to be known as Mad Cow disease. Scientists began to suspect that this was somehow related to some human illness. A California neurologist said both humans and animals were suffering from a mutated prion. When defective prions are transmitted from an infected host to a new host, they convert any normal prions they come across into copies of themselves so it is possible for a mutated prion to be transmitted from a cow to a person by eating beef. Dr. Stanley B. Prusiner received a Nobel prize for his work with prion.

In 1996, more than a dozen children in Seattle, Washington, were fighting for their lives. Each one of them had contracted a serious illness, and no one knew what it was. When one of the children died, investigators knew the clock was ticking and they needed to isolate the cause and find the cure before time ran out.

Exploring how an American hit single from 1966 -- the cheater by Bob Kuban And The In-man -- foreshadowed the demise of the group's lead singer, Walter Scott (Walter Notheis Jr.), who disappeared in 1983.

No one in a quiet residential community saw or heard anything unusual the day one of their elderly neighbors was brutally attacked and murdered. Fingerprints found at the crime scene and surveillance video from a security camera help investigators to apprehend the presumed killer within twelve hours, even though he'd already left the state on a bus, headed for New York City. [also marked as S8:E23]

In 1987, a human skull and some bones were discovered at a Boy Scout Camp near Farmington, Missouri. A facial reconstruction aided the investigators in this case. Once the victim was identified as Bun Chee Nyhuis, her husband Richard H. Nyhuis, was no longer just a person of interest.

Mark Fair left for work and his fiancée Karla Brown stayed home. Later, Mark found Karla dead. Karla's body told police that she was a victim of sexual assault. During the autopsy, they were able to re-examine bite marks on her body. A computer gave a view of the marks and forensic odontology identified the killer.

In 2000, when teenager Tara Munsey goes missing after a work shift at a Virginia restaurant, it is unknown if she ran away or if she was the victim of foul play. Everyone's worst fears are confirmed when a body is found at the bottom of an isolated ravine. Investigators scoured the crime scene, hoping to find enough evidence to identify the killer.

When the wife of a well-known dentist is found dead, police are unsure who killed her. Some fibers and a study of the weather patterns on the night of the murder break the case open and reveal the real killer.

An 18-year-old Ohio woman, who is abducted and then released soon afterwards, uses her knowledge of forensics to lead police to the kidnapper.

An aspiring model turned up dead, and the prime suspect was her boyfriend. When he was eventually cleared, investigators had to dig deeper to find the perpetrator. With the help of a forensic geologist, they identified the most unlikely suspects.

On March 13, 1981, 86-year-old Enid Whittlesey is found murdered in her Los Angeles home. The suspect eludes arrest for 16 years but that changes; however, when investigators learn the culprit is left-handed, putting a new spin on old facts. [also marked as S7:E39]

When a young mother and her infant son are found dead in a cornfield, the obvious suspect is the husband and father of the victims. But some insects found on the bodies reveal a vital clue, as does a long, blonde hair found on the victims.

When a woman's husband was gunned down in his own garage by intruders, investigators worked tirelessly to find the assassins. But when they discovered that a wound sustained during the attack by the grieving widow may have been self-inflicted, they turned to science to help them unravel a twisted tale of lust, greed and deception.

On November 8, 1999, Bruce Miller was found shot to death in the office of the Michigan auto-salvage shop he owned. There were no clues or forensic evidence found at the scene. But computer forensic experts found evidence of a crime that had everything - sex, lies and a video tape. [also marked as S8:E24]

A family vacation turns into a nightmare when the wife is found face-down in the lake. There are no witnesses and little conclusive evidence to help police determine if they're dealing with a suicide, an accident, or something more sinister... until a forensic pathologist uses a groundbreaking technique to discover the truth.

The woman in the back of the truck was flailing her arms, screaming. They thought she was doing something dangerous for the fun of it. But when they found a jacket near a pool of blood, they knew what they'd seen wasn't a joy ride; it was an abduction.

The medical examiner ruled the death an accident, but the detectives investigating the case thought the evidence at the scene indicated otherwise. It would take three years, an exhumation and a second autopsy to determine who was right.

A young TV news producer is raped and murdered in her apartment. Police identify two suspects, but both are cleared of any wrongdoing. The case stalls for more than a year, and then investigators turn to the Commonwealth of Virginia's DNA Databank.

n 1994, friends reported that Jack Reeves' mail-order bride Emelita Villa had disappeared. The police centered their suspicions on Reeves and, while pursuing leads, uncovered information linking him to the deaths of two former wives.

After a man's body is discovered a few miles from his home, authorities trace the crime back to his house and question his wife. (also shown as S7:E48)

When a young fireman died from what appeared to be serious but undiagnosed heart disease, his family and friends were devastated but they had no proof of foul play. Then they learned that, six years earlier in a nearby town, a young police officer died in the same way. The men had one thing in common: at the time of their deaths, they were married to the same woman.

A mother of two vanishes after a shopping trip. Her body is discovered a month later. Witnesses say they saw the victim being forced into a car by an unknown person.

How Illinois scientists solved a 1992 murder case involving cremation. It takes a long time and a very hot fire to cremate a human body, and thus destroy all evidence of foul play, but the coroner who performed the autopsy on the badly burned body of Charles "Jack" Lynch found telltale clues. Not only had the victim been burned, he’d also been stabbed -- 24 times, with two different knives. Police knew that a person, acting alone, would probably use only one weapon. So investigators were on the lookout for a couple of killers.

The investigation into a suspicious death hits a dead end when the autopsy indicates that no foul play was involved. But a telephone tip and the sensitive nose of a forensic examiner indicate otherwise. [also marked as S7:E38]

An infant was rushed to a Cleveland emergency room with serious breathing problems. The baby’s lungs were bleeding, a life threatening, extremely rare condition. Within months, there were more than 30 cases – an incidence more than a thousand times higher than anywhere else in the world. Doctors had never seen anything like it, and searched frantically for the cause and a cure.

A mother of two young children was found dead in her bedroom. It appeared she had killed herself: There were suicide notes near her body, and a pistol was in her hand. Her death was ruled a suicide – but when investigators learned she had almost died in a house fire three years earlier, they decided to take another look at the evidence.

Clayton Johnson, a Nova Scotia schoolteacher, left for work on the morning of February 20, 1989. At 7.40 AM, the school bus arrived to pick up the Johnson children. At 7.51 Mrs. Molloy arrived to drop off her child at the Johnson home. She found Janice Johnson lying at the bottom of the basement stairs in a pool of blood. A new life-insurance policy sparks suspicions of murder.

A look into the 1984 Oregon food poisonings, we're detectives track down the outbreak to a cult which aims to use germ warfare to take down the government. [also marked as S7:E16]

A suspicious fire swept through an apartment killing two young women. The cause of the fire and the identity of the victims were unclear. But a closer look at the fire scene revealed something hidden in the ashes.

Sometime during a neighborhood Christmas party, five-year-old Melissa Brannen disappeared. No one saw where she went or noticed anything unusual. Investigators turned to forensic science to help them see what the witnesses missed. The young girl was never seen again but fiber analysis led police to a suspect nonetheless.

At the age of 12, a boy's testimony helped convict the man who murdered his mother. Five years later, discrepancies in the autopsy lead him to question if the murdered woman really was his mother. If it wasn't, an innocent man had been sent to prison.

Although a group of teenage thugs are suspected of attacking two boys on a fishing trip, there is no solid evidence until a murky fishing hole provides some answers.

In 1997, two years after a series of unsolved kidnappings and sexual assaults in California. One of the victims suddenly recalled an important detail of the crime which she had not told police. She left some forensic evidence in the assailant's vehicle, evidence that left quite an impression.

In an affluent suburb of Philadelphia, police were called to the scene of what appeared to be an accidental drowning. The investigation gradually focused on one person, a suspect who had more than a million reasons to want the victim dead.

The victim had been sexually assaulted and stabbed to death on the beach, just ten yards from the hotel where she was staying. A pair of men's tennis shoes was discovered near her body. Police were sure that if they found the man who fit the shoes, they would also find the man who committed the crime.

Young Navajos on a reservation in the Southwest were dying at an alarming rate. CDC officials had never seen anything like it; the mysterious illness had claimed the lives of more than 20 people. The tribe's medicine men provided investigators with a critical clue which would lead halfway around the world to a most unlikely killer.

In 1988, when a young prostitute's body turns up in an Ohio waterway under ice, authorities have one tiny clue which could point to her killer, but face huge challenges due to her policemen clients and DNA evidence being washed away.

In the mid-1980s, bodies of nude woman were found in remote hill of California. The killer gags and molests prostitutes, cuts their clothes in random patterns and cuts off their hair; microscopic evidence helps solve the case.

In Pennsylvania 1984, a passer-by finds the torso of a woman in a cardboard box. Investigators rely on insect activity analysis by a forensic entomologist to determine when the murder victim was killed. She remained unknown until a year later, when her sister called to report her missing. Eventually she was identified and a man was convicted of her murder, but would further forensic entomology change the outcome?

Firefighter Michelle Baker became pregnant by her lover, Dr. Maynard Muntzing. After this news, she was ill whenever they were together. The coincidences led her to suspect that he was doing her harm, so she set out to prove it.

In 1962, the people of the small town of Hanford, CA lost their sense of peace when one of their own, 15-year-old Marlene Miller, was murdered. Booker T. Hillery was convicted and after countless appeals, Hillery received a re-trial in 1983. Forensic scientists had to use new knowledge of microscopic evidence to be able to place Hillery at the scene.

In 2008, college co-ed Jenna Verhaalen was found dead in her Bryan, Texas apartment and petechial hemorrhages in her eyes indicated that she was strangled. The victim's boyfriend, a neighbor and the apartment maintenance man are all suspected, but it takes DNA evidence to identify the killer.

When teenager Rosemary Anderson is found dead on the side of the road, her boyfriend eventually confesses to her murder, but in a strange twist, so does another man – serial killer, Eric Edgar Cooke. It would take the passage of another forty years, an author, and an expert in the field of pedestrian accident reconstruction to determine who was telling the truth. [also marked as S8:E26]

A murder investigation in St. Petersburg, Florida, crosses jurisdictions from New York to Jamaica. The police use cell phone mapping, wiretapping and a host of forensic evidence to find a surgeon's killer. [also marked as S7:E47]

The murder of an eccentric millionaire was not entirely unexpected; he flaunted his wealth and cared little for personal security. The evidence at the crime seemed to indicate robbery, but investigators wondered if there was something more.

The killer probably hoped to cover his tracks by staging the crime scene. But investigators saw through the attempt almost immediately, and they turned to forensic science to learn what really happened that night. [also marked as S12:E19]

A look back at the case of the River Park Rapist, who sexually assaulted four women in South Bend, IN, during 1996. Law enforcement officers arrested Richard Alexander, who was convicted in 1998 and sentenced to 70 years in prison. In 2001, Michael Murphy confessed to one of the two rapes of which Alexander had been convicted and forensic developments reveal new facts about the case.

In 2004, Mary Ann Clibbery was found brutally murdered in her Illinois business and investigators had to determine if this was a robbery gone wrong or a calculated murder. The evidence at the scene told police what happened and they got a huge break when evidence from the murder was found on top of a nearby frozen river.

The tragic murder of 9-year-old Jessica Knott is investigated; a garbage bag leads investigators to her killer. [also marked as S7:E34]

A man disappears one year to the day after beginning an affair with his friend's wife. 15 years later, with the help of a metal detector, police found evidence which would prove what had happened, and who was responsible.

When police recovered the submerged car of a man reported missing, they expected to find his body – but it wasn't there. His broken eyeglasses were on the floor of the vehicle and the interior was coated with motor oil. The investigation which followed would uncover an obsession turned deadly, and the motive for murder. [also marked as S10:E19]

Robert Sims returned home after working the night shift, and found his wife, Paula, unconscious on the kitchen floor. Their two-year-old son, Randy, was asleep in an upstairs bedroom, but their six-week-old daughter, Heather, was missing. Paula Sims was the only witness to a crime that baffles investigators to this very day.

Early one fall morning, Laura Houghteling left her Bethesda home and walked to the station to take a train to work. She was never seen again. A peculiar strand of hair found in Laura’s hairbrush enabled investigators to unravel the mystery of her disappearance.

Alarmingly high levels of thyroid hormones pump through the systems of South Dakota residents. Investigators study one family who all got sick, except their 12-year-old son who is a vegetarian.

A mother and her two young daughters are found brutally murdered. The crime scene yielded a good deal of evidence, but no conclusive link to the prime suspect. To solve the puzzle, an FBI analyst designs a unique experiment.

Escherichia coli (E-coli) bacteria can be found in meats, milk and in water. When food is properly processed, prepared and stored, E-Coli are harmless. But in the absence of these simple precautions, E-Coli can have deadly consequences. Raw Terror tells the story of Damion Heersink, an eleven-year-old boy who almost died after eating an improperly cooked hamburger teeming with E-Coli, and the people who saved his life.

The 1987 disappearance of Houston resident Tracy Jo Shine is recalled. The investigation went cold until 2000, when a "cold case squad" learned that the woman's ex-boyfriend Michael Neal had bragged about killing her.

In 1986, Gary Dale Larson was stabbed to death in his Edmond, OK, home and then the killer sexually assaulted Larson's girlfriend Janet Haynes. Hayne's story seemed farfetched: The perpetrator was wearing only underwear and gloves broke into the house, stabbed Larson to death, then raped and terrorized her for hours afterwards. But, the evidence at the scene supported her story, and investigators turned for help to the FBI and their criminal profilers.

In Omaha, the deaths of a child and a truck driver in the same hospital on the same day are investigated to see if there is a link between them.

In 1996, police received a call from Darlie Routier telling them of her two sons' murders. However, investigators were not certain about the validity of Darlie's story and began an intensive search of the crime scene. The police found out who the killer was by analyzing blood spatter, doing behavioral profiling and analyzing Darlie's 911 call.

An obstetrician returned home from the hospital and found his wife on the floor of the bathroom. She was covered with blood and not breathing. He tried unsuccessfully to revive her, staining his clothes with her blood in the process, and then he called 911. His version of events was not supported by the blood spatter evidence, and investigators had to determine why. [also marked as S10:E17]

In 2005, the body of young mother Summer Baldwin was found in a suitcase in a Texas landfill. The suitcase leads investigators to a suspect, Rosendo Rodriguez, and the forensic evidence against him was formidable. Further evidence leads them to teenager Joanna Rogers, who had gone missing in 2004. Upon extensive search of the same landfill, Rogers' decomposing body was also found in a suitcase.

When a sexual predator murders two young boys in Nebraska within three months of each other, an obscure style of rope and forensic analysis lead to his arrest and conviction.

When a college student is reported missing, police believe their investigation will be like countless others, and she'd turn-up a few days later. But when they discover blood spatter in her boyfriend's bedroom, blood spatter someone had gone to great lengths to conceal, they know this case is going to be different.

In 2003, Tiffany Rowell and three of her friends were brutally murdered in their affluent Clear Lake, TX, neighborhood and the crime scene yielded little evidence. The next-door neighbors had seen two young people dressed in black walking nearby and their descriptions were used to create composite drawings, which become a key element in solving the crime.

A wealthy man and his wife were attacked by three men outside their luxurious Louisiana home. He was shot dead and she was forced to open their hidden safe. The woman could not describe the men because they wore masks. To solve the case, police would have to find out who knew about the concealed safe, and who would benefit from the crime.

Caren Campano disappeared and her husband, Chris became the prime suspect -- especially after police found a huge bloodstain on the Campano's bedroom carpet. When they sprayed the bedroom with Luminol, they discovered it was awash with blood spatter. Complex DNA testing - 'reverse paternity' tests - proved it was Caren's blood. Now all they had to do was find her body.

When Missouri police in the Great Plains were called to retrieve a dead body, they did a background check on the victim. The trail guided them into a strange thread of homeless drifters, cattle auctions and bad checks.

A car was found in a drainage ditch and the bodies of a man and woman were inside; both had been shot to death. The car windows were broken and shattered glass should have been everywhere, but it wasn't. A fingertip torn from a latex glove would point investigators to both the crime scene and the killer.

Emergency dispatch received a call from a man who said his girlfriend shot and killed herself. Police found the victim in the caller's house, lying in a pool of blood with the gun next to her on the floor. The autopsy revealed that the gunshot wound was not self-inflicted and the evidence found on her body would give police a golden opportunity to catch her killer.

When an off-duty policeman was shot dead, his fellow officers were determined to solve the crime. They needed clues to find the killer, and they discovered them in tiny fibres and an asthma inhaler.

In 1993, the Amtrak Railroad experienced the deadliest train crash in United States history when the Sunset Limited derailed while crossing Alabama's Big Bayou Canot bridge. Forty-seven passengers and crew were killed; scores more were injured.

A go-go dancer told her family she needed to get away for a while, and then she simply disappeared. Investigators were suspicious, because she took neither her car nor her clothes. The next twenty years passed slowly, and the family began to think they might never know what happened until they received a phone call which changed everything.

It was one of the most brazen crimes of the 20th century. Adolph Coors, chairman of the Coors Brewing Company, was kidnapped and held for ransom prompting one of the most intense manhunts in United States history.

In the back woods of Georgia, in a dilapidated house, a 49 year old recluse named Virginia Ridley was found dead. A medical examiner ruled the death a homicide. But who would murder someone who seldom ventured out of her home? Investigators found some clues in the notes she had written shortly before her death.

Two men were convicted of intentionally shooting and killing a passenger in a moving car, their friend was granted immunity for testifying against them, and the case was closed. Then a bomb exploded in the family home of the state's witness, instantly killing his father. Investigators turned to forensic science, hoping to determine if this was an act of revenge and if there was a way to link the two deadly crimes.

When a woman went missing, friends and family were determined to find her. Their worst fears were confirmed weeks later when her body was discovered. Blood evidence and computer forensics helped investigators to catch the killer, and convince the jury of his guilt.

In 1989, 19-year-old mother Lori Auker left her Pennsylvania home for work, but never arrived. It takes space-age technology, cat hairs and insects to help build an image of the woman's abductor.

The victim was a self-made man who never minced words. Perhaps he was murdered by a disgruntled client or employee. Perhaps the racy photos in his safe held the clue to solving the crime. Or perhaps with the help of the IRS, investigators could follow the money and find the killer.

In 1981, six-year-old Cassie Hansen disappeared from her St. Paul, Minnesota church during a Sunday evening service. After a tip from a witness that an older man was seen carrying a small body, Cassie's body was found in a dumpster. The FBI created a psychological profile of the perpetrator, but are still unable to find the killer.

In a small South Carolina town in 1991, 17-year-old Crystal Faye Todd, a popular high school student, is raped, murdered and dumped in a deserted field, after attending a party. With few leads, authorities test the DNA of several friends and one match shocks everyone.

In 1995, Palm Beach waitress Denise O'Neill is abducted and murdered. Her neighbor, Luis Caballero, arouses suspicions by his odd behaviour towards TV crews covering the crime.

In 1990, Shirley Andronowich's body was found one morning after she was murdered and mutilated. Eyewitnesses told police Shirley and her husband Ed were seen fighting in a bar the night before. Police first suspected Ed and even arrested him after he confessed to the murder. But all forensic evidence proved that Ed had actually nothing to do with the crime.

A talented television news anchor was shot to death outside her home; it appeared to be a crime of passion, perpetrated by an obsessed fan. A police dog tracked the scent of the killer through the adjacent woods and back to the crime scene. Could the murderer be one of the onlookers, watching the police conduct their investigation?

A woman was brutally murdered in her home, and the only witnesses to the crime were the family dogs. An expert in canine behavior was convinced the killer knew both the victim and the animals, and he was determined find out exactly what the dogs had seen.

In 2000, the body of exotic dancer Rachel Siani was found beneath a New Jersey bridge and investigators wondered if she had committed suicide. Evidence at the scene proved not only that she'd been carried to the bridge and thrown over the side, but also that she was alive when she fell. Police look at customers at the gentlemen's club and co-workers who had vendettas against the victim.

Scott Dunn was missing and when the police sprayed his bedroom with Luminol, a scene of horrific violence emerged. Now investigators faced a daunting task: to prove Scott Dunn had been murdered, even though they had no body, no weapon, and no witnesses.

A union official is executed in his home not long after a strike by the union membership. Neither his wife nor anyone in the neighborhood heard any gunshots. It would take a forensic sound test, an electron microscope, and a nightgown to explain why.

A 1995 fire razes the mansion of Kansas doctor Debora Green, killing two of her three children; disturbing accounts from her ex-husband, Mike Farrar, lead investigators to believe she set the blaze herself.

In 1996, 17-month-old Josh Hinson died in a fire in his North Carolina home. A federal agency ruled that a fire was intentionally set and Josh's mother Terri Strickland was charged with murder. Using the then-emerging resources of the Internet, Terri Strickland undertook her own investigation. An independent fire investigator was able to poke enough holes in the government's scientific conclusions to raise serious questions about whether the fire was intentionally set.

Police initially suspect that the death of a gay student is a hate crime, until just three strands of hair and some microscopic cells help them unravel a web of lies, and to find the real motive for the murder.

When a hit-and-run accident claimed the life of a high school athlete, everyone in town mourned his passing. Finding the killer was a long shot at best, but investigators hoped tiny paint chips and pieces of plastic found at the scene would lead them to the person who was behind the wheel.

The year was 1984, and a serial killer was on the loose in Florida. Eight women had been found dead. At each crime scene, investigators found tiny red fibers, fibers they hoped would lead them to the killer.

Between 1985 and 1988, 18 people were choked, molested and left for dead in the remote desert mountains of California. The only witnesses were the insects – and they also proved to play an important role in solving the crimes.

Threatening emails, a missing person and an abandoned truck lead police to a home where they believe a murder was committed. The evidence is overwhelming and investigators are sure they have the killer. What they don’t have is the body of the victim.

On Christmas eve 2005, the corpse of a black male is found burning near Baltimore. He's eventually identified as 26-year-old Wesley Person. Distinctive building materials from the 1930s found near the body play a crucial role in solving this case.

Dianna Green was just 20 years-old and pregnant when she was brutally raped and beaten in her apartment. The assault caused the death of her unborn baby. When Dianna came out of a coma 3 weeks later, she told police she knew the identity of her attacker. But was her memory accurate?

In 1992, two masked gunmen enter the Canadian home of Ward and Diana Maracle to rob them, but Ward was shot in the head. If a perpetrator leaves a shoe print in the mud, investigators use established techniques to make a mold of the shoe impression for later identification. In this case, the impression is left in the snow. Here's the story of one investigator, whose quick thinking and knowledge of science enabled him to capture a shoe impression made in snow, before the evidence melted away.

The use of the computers by law enforcement is detailed in this look at a series of crimes in St. Louis that stumped the local police and the FBI. (also marked as S7:E44)

A woman was found dead on the bedroom floor of her apartment. The crime scene yielded little of value, and investigators wondered if they would find enough evidence to make a case, much less catch a killer. But a bloodstained sheet and a breakthrough forensic technique enabled them to identify the murderer, and convince the jury of his guilt.

In 1994, Paul Gruber's daughter suspected something was wrong when she received birthday cards addressed from Gruber, on which the handwriting wasn't Gruber's. When she then learned virtually everything had been removed from her father's Sandpoint, ID home, she was sure of it. Even though she lived almost a thousand miles away, she took it upon herself to find out what happened and who was responsible.

In 2006, Texas real estate agent Sarah Anne Walker was found brutally murdered in a model home. Weeks later, a witness came forward who may have seen the killer and police used forensic hypnosis to help him recall every detail of the man's appearance. His description was used to create a composite sketch, which police used to draw the killer out of hiding.

The investigation into the apparent overdose suicide of Reverend Bill Guthrie's wife Sharon. Detectives suspect foul play after they recover incriminating files from Bill's computer and learn of his infidelity.

For twelve years, the murder of a young woman went unsolved, but with the passage of time came the development of technology. Would a used tissue found at the crime scene give police the evidence they needed to crack the case and bring a killer to justice?

The 1996 investigation into 48-year-old Martha Hansen's murder in Anchorage is helped by a legal requirement that bars have video cameras installed on the premises. Using video, hair and blood evidence, investigators determine who her murderer was.

In 2001, Ginger Hayes and her infant son Nicholas were abducted during a carjacking and the crime had been reported by a witness within minutes of occurrence. 45 minutes after the kidnapping, When Ginger and Nicholas were found 50 miles away, Ginger had been beaten to death, but Nicholas was still alive. Further analysis of Ginger's car and evidence at the scene where Ginger was found both led to her killer.

A woman who was known to have suffered from depression apparently took her own life. But her sister told police that, a year before her death, she said if anything were to happen to her, there was a note in the china cabinet. Investigators found the note and the killer.