A federal investigation into who supplied actor Matthew Perry with ketamine before his death last year could result in charges against several people, a law enforcement source familiar with the probe told NBC News on Wednesday.

In May, the Los Angeles Police Department said it was working with the Drug Enforcement Administration and had an “open investigation” into the source of Perry’s ketamine following his Oct. 28 death at his home.

The law enforcement source said that the federal probe remains ongoing and there would be no immediate action in the case. People magazine was the first to report the news.

Perry, 54, best known for his role as Chandler Bing on “Friends,” was found unresponsive in his pool, according to the Los Angeles County Medical Examiner’s Office. He died from the acute effects of ketamine with contributing factors including drowning, coronary artery disease and the effects of buprenorphine, a synthetic opioid used to treat opioid use disorder, the medical examiner’s office said.

The actor had been open about his past drug use but had reportedly been clean for 19 months, the medical examiner’s report said. Perry reportedly was receiving ketamine infusion therapy to treat depression and anxiety with his last treatment being 1½ weeks before his death, according to the coroner.

But the coroner said the levels of ketamine still in his body were high, around what is used for general anesthesia during surgery. The coroner said it was unclear why the drug would still be in his system since it metabolizes within hours.

Perry’s death is also being investigated by Los Angeles police.