Investigators seek the spirit of the infamous Ted Bundy, serial killer, rapist, kidnapper, and necrophile who assaulted and murdered many young women between 1974 and 1978. After more than a decade of denials he confessed to 30 homicides shortly before his execution; the true total remains unknown, and could be much higher.

Investigators seek the spirit of Charles Raymond Starkweather. He was only a teenager when he murdered eleven people in Nebraska and Wyoming while on a road trip with his girlfriend. The couple were captured on January 29, 1958.

Investigators seek the spirit of Richard Trenton Chase, a United States serial killer who killed six people in the span of a month in Sacramento, California. He was nicknamed "The Vampire of Sacramento" because he drank his victims' blood and cannibalized their remains.

Investigators seek the spirit of Albert Henry DeSalvo, aka "The Boston Strangler." After the murderer of 13 women in the Boston area, DeSalvo was not imprisoned. However, he was jailed for a series of rapes. His murder confession has been disputed, and debate continues regarding which crimes DeSalvo actually committed.

Investigators seek the spirit of John Wayne Gacy, Jr., also known as the Killer Clown. He raped and murdered 33 teenage boys and young men between 1972 and 1978 before being caught.

Investigators seek the spirit of Aileen Wuornos, an American serial killer who killed seven men in Florida between 1989 and 1990, claiming they raped or attempted to rape her while she was working as a prostitute.