Police searching for source of ketamine obtained by Matthew Perry

(NewsNation) — Police are investigating how actor Matthew Perry obtained the ketamine that ultimately killed the “Friends” star last year, the Los Angeles Police Department confirmed to NewsNation.

A bystander found Perry, 54, dead in a hot tub Oct. 28 at his Pacific Palisades residence. Perry died before first responders arrived. Toxicology and autopsy results showed the actor died from “acute effects of ketamine.”

Drowning, coronary artery disease and buprenorphine effects were contributing factors, according to the report. Buprenorphine is used to treat opioid use disorder. Perry was reported to be receiving ketamine infusion therapy for depression and anxiety.

According to the medical examiner's report released in December, "high levels of ketamine" were found in Perry's blood specimens. However, the report noted his last known treatment as almost two weeks prior to his death, meaning the ketamine “could not be from that infusion therapy, since ketamine’s half-life is three to four hours, or less.”

Officials, however, are attempting to trace the origin of the ketamine that medical examiners found in Perry’s system from the night he died.

The police department did not provide further details about the investigation.