CHICAGO (CBS) — A court appearance is scheduled today for the Naperville woman, accused of murdering her son and the child she was babysitting last week.

Elzbieta Plackowska is being held without bond after the killings of her 7-year-old son Justin and 5-year-old Olivia Dworakowski at the Dworakowski’s Naperville townhouse.

She also killed two dogs in the home.

The Naperville Sun reports prosecutors are expected to ask the judge to order a psychiatric evaluation for the 40-year-old woman as they prepare for her possible insanity defense.

Her lawyer has separately asked for a psychiatric exam.

Prosecutors say Plackowska gave different reasons for repeatedly stabbing the children.

Among those: That she needed to drive evil out of them.

But, they say, she later admitted she killed her son because she was angry at her husband and then killed Olivia because she was a witness.

LISTEN: WBBM Newsradio’s Regine Schlesinger Reports

Watch & Listen LIVE