Carpentersville woman pleads guilty but mentally ill in fatal stabbing of sister

A Carpentersville woman pleaded guilty but mentally ill Friday to the fatal stabbing of her sister.

On Sept. 29, 2014, Sandra L. Baumgartner, 56, stabbed her sister, 57-year-old Sharon Baumgartner, at her apartment in the 100 block of South Lincoln Avenue in Carpentersville, according to the Kane County State’s Attorney’s Office.

Officers found the elder Baumgartner bleeding heavily, and she died a short time later, Carpentersville police said at the time. Officers later found Sandra Baumgartner in a wooded area nearby after a search lasting several hours.

Both women lived in the same building, but in separate apartments, police said.

In affidavits filed in Kane County, police said Sandra Baumgartner appeared to be suffering from mental illness. During their investigation into the fatal stabbing of her sister, officers spoke with a local psychiatrist who said he last saw Sandra four days prior to the slaying. He said he had recently changed the woman’s anti-psychotic medications, and that he had been concerned about her recent behavior and history of violence.

This was not the first time those close to Sandra Baumgartner had been concerned about her long-standing mental illness. According to court records, officers were called to Sandra Baumgartner’s Carpentersville home in July 2013 after Sharon Baumgartner reported concerns about her sister’s increasingly erratic behavior.

Sharon Baumgartner told police that her sister was delusional and that she was especially concerned because in 2001, Sandra Bumgartner had been charged with stabbing a man 120 times in Memphis. She was found not guilty by reason of insanity, institutionalized, and eventually moved into the apartment building in Carpentersville.

Sandra Baumgartner is being held at the Kane County Jail in lieu of $1 million bail, prosecutors said. Friday’s finding of guilty but mentally ill means that she may receive mental health treatment as available from the Illinois Department of corrections. She has been diagnosed with schizophrenic affective disorder bi-polar type.

Sandra Baumgartner’s next court date was set for May 17, prosecutors said. She faces up to 60 years in prison.