World's Most Evil Killers

Vincent Tabak strangled his neighbor to death in her own apartment in December 2010.

John Cooper, known as The Bullseye Killer, killed four people between 1983 and 1996.

Christopher Halliwell's found guilty of murdering two women.

Trevor Hardy, known as The Beast of Manchester, killed three teenage girls in a series of brutal attacks.

Dennis Rader, known to the world as the BTK Killer, killed ten people, including young children, between 1974 and 1991 in Wichita, Kansas.

David Heiss stabbed Matthew Pyke 86 times after he became infatuated with Matthew's girlfriend.

In August 1990, Danny Rolling murders five college students in Gainesville, Fla., home of the University of Florida, and creates gruesome crime scenes that are designed to shock.

In Cumbria, 2010, taxi driver Derrick Bird took his gun and shot dead 12 people and injured 11 more.

Serial killer Bob Berdella, aka the Kansas City Butcher, kidnaps, rapes, tortures, and murders at least six men between 1984 and 1987 in Kansas City, Mo., forcing his victims to endure periods of up to six weeks of captivity.

Bobby Joe Long is on Florida's death row for abducting, sexually assaulting and murdering at least 10 women in the Tampa Bay area during an eight-month period in 1984.

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

Scottish serial killer Robert Black attacked four young girls between 1981 and 1986; he was sentenced to life imprisonment at HMP Maghaberry with a minimum sentence of 35 years and was linked to 13 other child murders.

Robert Lee Yates kills 13 prostitutes in Spokane, Wash., between 1996 and 1998 and later confesses to two other murders committed in 1975 and 1988.

From November 1989 to November 1990, Aileen Wuornos kills at least six men in Florida.

In 1977, Angus Sinclair kidnapped, raped and murdered two 17-year-old girls.

Colin Ireland made a New Year's resolution in 1993 to become a serial killer and then murdered five gay men.

Serial killer, kidnapper, rapist, burglar, necrophile and pedophile Ted Bundy confesses to 30 homicides he committed in seven states between 1974 and 1978.

A look at Gary Ridgway, also known as the Green River Killer, and his reign of mass murder across the Pacific Northwest for almost 20 years.

Diane Downs was convicted of the May 1983 murder of her daughter and attempted murder of her other two children, yet she told police a stranger had attempted to carjack her and had shot the children.

A profile of Karol Kot, also known as the Vampire of Krakow, who killed an 11-year-old boy and an 86-year-old woman, before attempting to kill more in prison.