MSN.com reports that a woman who was convicted of killing her disabled daughter has apparently committed suicide. Bonny Liltz, 57, was found guilty in 2015 for killing her disabled adopted daughter and was found dead in her apartment in the Chicago area over Thanksgiving weekend. She was due to return to prison on Monday to serve her sentence for the crime.

Liltz was pronounced dead at the scene Saturday of an apparent suicide, said the Cook County Medical Examiner’s Office.

The court ordered Liltz to return to prison on Monday to serve the remainder of her four-year sentence on November 21. She was found unresponsive in her bed by her sister.

Thomas Glasgow, Liltz’s attorney, told reporters that she had lunch with her father on Friday and spoke to her himself that afternoon. She then went to her mom’s house, telling family she was going to lunch and a movie with a friend. She wasn’t answering her phone, so her sister (who lives with their mother) went to the house and found Liltz’s body.

Schaumburg police say that no signs of foul play were observed and they believe it to be a suicide case.

Liltz was sentenced to a four year prison term in 2016 for giving her 28-year-old daughter, Courtney, a fatal dose of drugs. Liltz tried to commit suicide at that time as well but failed. Courtney suffered from cerebral palsy and cognitive defects due to a seizure when she was two years old. Liltz was also suffering from cancer and other health issues and pleaded guilty to manslaughter charges.

Liltz served 73 days of her sentence then was released on bond in August. The Illinois Supreme Court declined to hear her case, says Glasgow.

A suicide note was left for her family, stating she couldn’t go back to prison.

In 2015, Liltz believed she was dying and was afraid for her disabled daughter should she die. She had to put Courtney in a nursing home when she underwent surgery for cancer in 2012 and her daughter was severely neglected during her stay. Liltz explained to the judge she was afraid the same thing would happen to Courtney if something happened to her.

Liltz then made a cocktail of drugs to inject into Courtney’s feeding tube and washed her own down with wine. Family members found them both unconscious and they were taken to the hospital for treatment. Courtney never recovered and died a week later.

*Photo courtesy of Bonnie Liltz/MSN.com