
An in-depth look at some of the world's most dangerous murderers.

On the surface, Zahid Zaman portrayed himself as a pillar of the community, but the true story of this cult killer was deeply sinister.

Gardener William Howell used his van as a "murder mobile," killing women and dumping bodies.

Christopher Halliwell's found guilty of murdering two women.

Four vicious murders put Mark Hobson at the center of a nationwide manhunt. Criminologists and psychologists try to decode this enigma.