Amanda Antoni's husband finds her body in their basement with blood everywhere. The scene confounds police: Was it foul play — or a tragic accident?

When an aristocrat and his entire family disappear, the authorities unearth something horrifying.

After rushing from his home, Rey Rivera disappears. Days later, his car is found — and a strange sight at a historic hotel triggers a baffling mystery.

Twenty-year old Josh Guimond leaves a college party without a word and is never seen again. Two decades later, his loved ones just want answers.

After checking in at a luxury hotel with no ID or credit card, a woman dies from a gunshot. Years later, her identity — and her death — remain a mystery.

Tiffany Valiante, a promising young athlete, is struck by a train four miles from home. But was her death a suicide or something more sinister?

A beloved father is brutally mutilated, but his presumed killer, a woman he knew from high school, escapes without a trace.

After a teen finds an embalmed head in the woods, investigators uncover a possible connection to a black-market organ trade as they try to ID the victim.

Lena Chapin claims on tape that her mother killed her stepfather. Several years later, she's issued a subpoena to testify in court — then disappears.

Paranormal researcher Don has an odd co-worker: an entity named Becky. A parapsychologist observes Don and Becky at work and is stunned by his findings.

Amid eerie sightings of a tall, winged humanoid creature with red eyes, paranormal investigators explore the Mothman's seeming link to major disasters.

For decades, a wave of cattle mutilations executed with near-surgical precision has plagued the US. Are extraterrestrials behind these gruesome acts?

In 1947, an unidentified flying object crashed near Roswell, NM. Was it a spy balloon or an alien encounter? UFO experts unravel the iconic mystery.

Bigfoot, orbs, UFOs, poltergeists and skin-walkers. For these Navajo Nation rangers, paranormal activity is just part of the job.

Residents of Berkshire County, Massachusetts, recall their baffling, terrifying experiences with a UFO on the night of September 1, 1969.

A massive earthquake and tsunami devastated Japan in March 2011. Residents share stories of the spirits they encountered in the wake of the disaster.

When a child is kidnapped by their own parent, what recourse does the family have? These two cases explore the unique pain of parental abduction.

London, 1888. The city is gripped by a string of murders, each more gruesome than the last. Experts delve into one of history's most notorious mysteries.