Karla Homolka
The Canadian woman with the looks of a glamorous TV star helped her husband, Paul Bernardo, rape and murder at least three teenage girls, including HER OWN SISTER, in the 1990s. At her trial, she entered a bargain plea by testifying against her partner in crime (as well as in marriage), and her own charge was downgraded to manslaughter. Bernardo claimed that his wife actually killed the victims once he was done abusing them. She served 12 years in prison and was released in 2005.