(MCT) — CHICAGO — An Illinois mother who left her daughter in the care of a baby sitter while she went to work learned after a frantic search Tuesday night that her little girl had been slain by the caretaker, along with the caretaker’s own son, officials said.

The baby sitter, Elzbieta M. Plackowska, 40, was charged with two counts of first-degree murder Wednesday night, according to DuPage County State’s Attorney Robert Berlin. Sources said the woman had given various explanations for what happened, including hearing demonic voices that led her to stab the children to death.