Elzbieta Plackowska, 45, was caring for her seven-year-old son Justin and a friend’s five-year-old daughter, Olivia, in a Chicago, US, condo in 2012, when the kids refused to settle down for bed. In a frustrated frenzy, she grabbed a kitchen knife, told them they were “going to heaven” and stabbed them to death. While being interrogated, she was adamant someone had broken in and killed the children while she was out having a cigarette. However, she finally admitted she murdered her son to get revenge on her husband and she killed Olivia because she had witnessed the murder. Plackowska pleaded insanity, but the judge sentenced her to life behind bars for murder.