Los Angeles, California - Police said Tuesday they are investigating the ketamine overdose death of Friends actor Matthew Perry, who died at his luxury Los Angeles home last year.

Perry, who played Chandler Bing on the hit TV sitcom from 1994-2004, was found unresponsive in his pool at the age of 54, sparking a global outpouring of grief from fans and colleagues.

An autopsy found the cause of his death was "the acute effects of ketamine," a controlled drug that the recovering addict was understood to be taking as part of supervised therapy.

While only small amounts were found in his stomach, a high level was detected in his bloodstream.

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Just how the actor – who had reportedly not had a supervised infusion session for several days – obtained the drug is now the subject of a legal investigation.

"Based on the Medical Examiner's findings, the Los Angeles Police Department, with the assistance of the Drug Enforcement Administration and the United States Postal Inspection Service, has continued its investigation into the circumstances of Mr. Perry's death," a statement from the LAPD said.

Doctors and veterinarians often employ ketamine as an anesthetic, and researchers have explored its use as a treatment for depression. Underground users take it illicitly for its hallucinogenic effects.

Friends, which followed the lives of six New Yorkers navigating adulthood, dating, and careers, drew a massive global following and made megastars of previously unknown actors who became a fixture in millions of lives.

But Perry's comic talent, which brought him fabulous wealth, hid a darkness that left him struggling with addictions to painkillers and alcohol.

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In 2018, he suffered a burst colon – related to drug usage – and underwent multiple surgeries.

In his memoir Friends, Lovers, and the Big Terrible Thing, published in 2022, Perry described going through detox dozens of times. He dedicated the book to "all of the sufferers out there" and wrote in the prologue: "I should be dead."

"I have mostly been sober since 2001," he wrote, "save for about sixty or seventy little mishaps over the years."

His sudden death drew shocked reactions from Hollywood A-listers, his costars, and Friends fans worldwide.

"Oh boy this one has cut deep," said Jennifer Aniston, who played Rachel on the show.