A 31-year-old woman from Wisconsin has confessed to fatally stabbing her mother earlier this year, subsequently leaving her to die.

On Tuesday, Sierra Schoonover pleaded guilty to the murder of her 54-year-old mother, Heather Schoonover, but claimed insanity as a defense, court documents reveal. This plea indicates that while she acknowledges the act of stabbing her mother, she argues she was not mentally capable of understanding her actions were wrong at the time.

Judge Ellen Berz clarified in court, as reported by WKOW, a Madison ABC affiliate, “When someone pleads not guilty due to mental disease or defect, it is tied to whether the crime occurred. The plea addresses the individual’s ability to comprehend the wrongfulness of their actions and their ability to align behavior with legal expectations. It is not about whether the offense occurred.”

Schoonover faces a charge of first-degree criminal homicide, with her next court appearance scheduled for October 23.

According to a criminal complaint referenced by WKOW, the incident took place on April 14, shortly before noon, when neighbors called 911 after witnessing a confrontation between the Schoonovers outside their residence on Smoky Mountain Road in Blue Mounds, roughly 30 miles from Madison. The altercation continued indoors before Sierra Schoonover fled in a vehicle.

Upon arrival, deputies from the Dane County Sheriff’s Office discovered Heather Schoonover deceased in the bathroom with multiple stab wounds. A knife was located nearby at the scene.

Not long after, Sierra Schoonover crashed her car a few miles away. She was naked, had a frothy substance on her mouth and dried blood on her hand, the affidavit said. Once at the hospital, she reportedly told deputies “I’m concerned my mom might be hurt, and so I think the ambulance should be sent for her.”

Cops asked her why she thought her mom may be in need of help.

“I stabbed her,” she reportedly responded.

A couple days later, she requested to speak to deputies again. She said she knew why they were there and needed to get something off her chest.

“I do know I killed my mom,” she reportedly said. “I remember everything that happened.”

Sierra Schoonover also said she had a history of anxiety and depression, but she had stopped taking her medicine.

The defendant was taken to jail, where she has been ever since.

Heather Schoonover’s obituary said those who knew her would describe her as “the nicest person they have ever met.”

“Heather always had projects going on at the house; she had many bins dedicated to crafting supplies as well as a woodworking set-up in the garage, with which she made many gifts for her loved ones,” the obituary said.