DuPage County State's Attorney Robert Berlin said Elzbieta Plackowska, 40, told investigators several stories, at first blaming the attack on a stalker who got into her home in Naperville, 25 miles west of Chicago. She later said the children had evil inside of them and she was fighting the devil in the house, Berlin said at a bond hearing.
Plackowska eventually admitted that she was angry with her husband, who works as a truck driver and is often gone, because he left her alone to care for her son, Justin, and work as a maid, which she felt was beneath her, Berlin said.
"She told the detectives that she thought by killing Justin she would make her husband hurt the way she hurt in their relationship," Berlin said.
Plackowska told investigators she found the children jumping on the bed and then attacked them, also slitting their throats, Berlin said.
"She had grabbed a knife and she made both victims kneel and begin praying. She began stabbing her son Justin and told him he was going to heaven tonight. He pleaded for his life and told her to stop. But she continued stabbing him until he was dead," he said.
"She then turned her attention to 5-year-old Olivia and began stabbing her with the knife multiple times. She as well pleaded for her life, but the defendant continued to stab her until she was deceased."
Plackowska killed the girl, Olivia Dworakowski, because the child had witnessed the attack on her son, Berlin said.
DuPage County Judge John Kinsella ordered Plackowska held without bond. Plackowska didn't speak during the hearing other than to indicate she could not afford an attorney. The judge appointed a public defender.