What drives a person to make a living out of killing? Mariana goes inside the dark world of contract killers.

Mariana investigates a new blackmail scam called "sextortion", in which compromising photos are used to extort victims and often leads to suicide.

Mariana exposes how black market operators are profiting from the sale of stolen human remains on secret marketplaces in the U.S. and beyond.

The high cost of prescription drugs has pushed millions of Americans to the black market — and into hands of criminal syndicates looking to cash in.

Mariana heads to the Congo to investigate the illegal trade in wild apes that have them on the brink of extinction.

Mariana heads to Mexico to investigate the billion-dollar business of people smuggling to the US — a system fueled by cartels and corruption.

Mariana tracks the illicit path of hashish from Morocco into Europe — a world of shadowy dealers, lightning-fast smuggling boats and endless wealth.

Mariana investigates a nefarious scam that tricks elderly Americans into becoming unwitting drug mules.

Mariana investigates a nefarious scam that tricks elderly Americans into becoming unwitting drug mules.

Mariana's investigation into how gold mining is funding terrorism gets interrupted by a military coup that strands the team in Niger.