Authorities are investigating Matthew Perry's death more than six months after the "Friends" star died at his home from the "acute effects of ketamine."
"LAPD has an open investigation," officials with the Los Angeles Police Department confirmed to Fox News Digital on Tuesday.
In addition, the Drug Enforcement Administration has teamed up with the LAPD to launch a criminal investigation into how Perry died, according to The Hollywood Reporter.
MATTHEW PERRY'S CAUSE OF DEATH LISTED AS ‘ACUTE EFFECTS OF KETAMINE’
Los Angeles Police Capt. Scot Williams said in an email Tuesday that the police department was working with the DEA and U.S. Postal Inspection Service into why Perry had so much ketamine in his system when he died in October, The Associated Press reported.
Perry died on Oct. 28 after an apparent drowning in a hot tub at his home in the Pacific Palisades area of Los Angeles. He was 54. "There were trace amounts of ketamine detected in the stomach contents," the autopsy listed. "The exact method of intake in Mr. Perry's case is unknown."
Other conditions that contributed to his death included "coronary artery disease, buprenorphrine effects," the report said. "Prescription medications and loose pills" were also found at his residence, according to the autopsy.
Ketamine is a dissociative anesthetic drug with "established medical and surgical uses," the autopsy detailed.
Perry reportedly received "ketamine infusion therapy for depression and anxiety."
WHAT IS KETAMINE, THE DRUG THAT KILLED MATTHEW PERRY ON OCTOBER 28?
His last known treatment was more than one week prior to death, but the medical examiner determined "the ketamine in his system at death could not be from that infusion therapy, since ketamine’s half-life is 3 to 4 hours, or less."
No foul play was suspected, and no illegal drugs were reportedly found at the scene. Perry was laid to rest Nov. 3 at Forest Lawn Memorial Park.
The "Fools Rush In" actor was already deceased when first responders arrived and found an adult male "unconscious in a stand-alone hot tub," according to Capt. Erik Scott. "A bystander had brought the man's head above the water and gotten him to the edge, then firefighters removed him from the water."
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Scott added that, following a "rapid medical assessment," the man was "deceased prior to first responder arrival" and that circumstances were under investigation by the LAPD and the LA County Medical Examiner. LA County Medical Examiner's office closed their investigation in December.
The case was moved on to the LAPD Robbery-Homicide Division, which is not uncommon because the agency often works with high-profile cases.
Perry, who was born in Massachusetts and raised in Canada, was 24 years old when he began portraying Chandler Bing on the sitcom "Friends."
"Friends," one of the most-watched shows on television, first debuted on NBC in 1994 and starred Perry, Jennifer Aniston, Courteney Cox, Lisa Kudrow, Matt LeBlanc and David Schwimmer.
