Mark Penley allegedly previously told a different ex-girlfriend he broke into Heather Bickford's home and watched her while she was asleep with new boyfriend Dana Hill.
On one occasion, Jacqueline Ades of Phoenix, Arizona allegedly broke into her victim's home and was taking a bath when police found her. They also found a large butcher knife in her car.
Renee Burke supposedly searched, "What car liquids could kill a human?" before getting caught on camera pouring a pink liquid into her estranged husband's wine.
Alan McGinnis pleaded guilty to murdering Cody MacPherson, who was entangled in a love triangle with him and Caitlyn Huertas, the mother of McGinnis' children.
Brian Winchester admitted to shoving his best friend, Mike Williams, into Lake Seminole, Florida before shooting him in the face. Now, Mike's wife, Denise, is on trial for allegedly masterminding the whole murder scheme.