MIDDLESEX TWP — Authorities are investigating the heroin-related death of a 31-year-old mother last week at her home on Park Drive.

Middlesex Township police did not release the woman’s name, pending completion of the investigation.

She died at a suburban Pittsburgh hospital Saturday, two days after she was found unresponsive at the house she shared with her mother and her two young children.

An autopsy ruled that she died of an accidental heroin overdose, a lack of oxygen to the brain and respiratory failure, according to the Allegheny County Medical Examiner’s Office.

The victim’s mother notified authorities Thursday after she kicked in the bathroom door and found her daughter lying on the floor, said police Sgt. Randy Ruediger.

Unspecified drug contraband was also found in the bathroom and in the woman’s purse.

“The items we found suggest heroin could be somewhat responsible for her death,” Ruediger said. He declined to elaborate.

The mother and a police officer administered cardiopulmonary resuscitation on the woman until a Quality Ambulance crew arrived.

Medics dispensed three doses of the opioid-overdose antidote naloxone but the victim never regained consciousness, police said.

She was taken to UPMC Passavant-McCandless and placed on life support until she was pronounced dead at 4:43 p.m. Saturday.

Ruediger said police have consulted with the Butler County District Attorney’s Office while they continue their investigation.

“We’re looking at all the evidence we have so far,” he said, “and that will help determine where it’s going to lead us next.”