Elzbieta Plackowska Case: Prosecutors want psych exam for mom accused of stabbing son, girl

(CBS) CHICAGO - Elzbieta Plackowska, the Chicago-area woman accused of fatally stabbing her son and a young girl that she was babysitting, appeared in court Thursday after prosecutors requested she undergo a psychological evaluation, the Chicago Tribune reports.

PICTURES: Cops: Ill. mom stabbed son 100 times, girl 50 times

Plackowska, 40, is being held without bond after the killings of her 7-year-old son Justin and 5-year-old Olivia Dworakowski at the girl's Naperville townhouse, CBS Chicago reports. She is charged with two counts of first-degree murder.

According to the Tribune, prosecutors want the exam in preparation for a possible insanity defense. The judge did not make a decision Thursday, scheduling another hearing for next Tuesday.

Prosecutors say that Plackowska stabbed her 7-year-old son, Justin, 100 times and stabbed 5-year-old Olivia Dworakowski 50 times.  Two dogs were also found slain inside the home.

Prosecutors say Plackowska gave different reasons for repeatedly stabbing the children, at one point saying she needed to drive the evil out of them, CBS Chicago reports.

Plackowska reportedly said later that she killed Justin because she was angry with her husband, and fatally stabbed Olivia because she had witnessed the attack on her son.

Complete coverage of Elzbieta Plackowska on Crimesider