
World's Most Evil Killers delves straight into the stories of the world's most prolific killers. Each episode focuses on one notorious killer and features first-hand accounts of their behavior; such killers range from Fred and Rose West, Ed Gein, the Clown Killer, to the Milwaukee Cannibal. Accounts are also given by detectives who ran the cases, journalists who reported on them, relatives, experts on analysis, and sometimes even survivors.

William Bonin is thought to have raped, tortured and murdered a minimum of twenty-one boys and young men.

The American serial killer Cesar Barone took the life of four women in and around Hillsboro, Oregon in the 1990s.

An examination of the Polish serial killer who came to be known as The Scorpion.

In 1999 and 2000, John Eric Armstrong cruised the streets of Detroit, Mich., looking for sex workers; seen as an ordinary husband, father and co-worker, no one in Armstrong's life suspected that he was a serial killer.