Harold Shipman was Britain's most murderous serial killer. He was responsible for the deaths of more than 200 people. In 2000 he was convicted in the death of 15 people and imprisoned. He died behind bars in 2004.
Jeffrey Dahmer, one of the most infamous serial killers of the 20th century, was arrested on July 22, 1991. Watch a short video in which he speaks about how his early obsession with violence unraveled into unthinkable crimes.