Woman pleads guilty but insane in mother’s brutal stabbing death

BLUE MOUNDS, WI — Sierra Schoonover, 31, pleaded guilty but not guilty by reason of insanity in the stabbing death of her mother, 54-year-old Heather Schoonover. The plea was entered on Tuesday during a court appearance.

Sierra admits to the act of stabbing her mother but claims she did not understand the wrongfulness of her actions due to a lack of mental capacity. Judge Ellen Berz addressed the court, stating, “Whenever someone enters a not guilty by reason of mental disease or defect plea, it’s coupled with a plea that goes to whether the crime was committed or not.”

Sierra faces a charge of first-degree criminal homicide. Her next court date is set for Oct. 23.

On April 14, neighbors reported a disturbance outside the Schoonover residence on Smoky Mountain Road. The altercation, which was observed from outside, eventually moved inside the home, after which Sierra fled the scene.

Dane County Sheriff’s Office deputies discovered Heather Schoonover dead in the bathroom with multiple stab wounds. A knife was located nearby.

Sierra later crashed her vehicle a few miles away, appearing disoriented and covered in blood. She reportedly told deputies at the hospital her concerns about her mother’s well-being.

Sierra’s statements to authorities confirmed her awareness of the situation. She recalled, “I do know I killed my mom,” and indicated she had a history of mental health issues.

The defendant remains incarcerated without bail. Heather Schoonover has been remembered as “the nicest person they have ever met” according to her obituary.

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