The death of actor Matthew Perry is the subject of a criminal investigation, according to law enforcement officials.
The actor from "Friends" passed away in December from what the Los Angeles County Department of Medical Examiner described as "acute effects of ketamine.
According to KTLA 5 News, the Los Angeles Police Department is now collaborating with the DEA and the US Postal Inspection Service to determine how and why the actor had such a high concentration of the drug in his system when he died.
about Tuesday morning, TMZ was the first to report about the probe.
"For his anxiety and depression, he was reportedly getting ketamine infusion therapy."
There was ketamine in Perry's system when he passed away, which "could not have been from that infusion therapy,
since ketamine's half-life is three to four hours, or less," according to the study. His last known treatment was 1.5 weeks prior to his death.