(NewsNation) — Police have launched an investigation into Matthew Perry’s death, and it may have to do with who provided him drugs.

What is happening in the Matthew Perry investigation?

A law enforcement source told People on Tuesday that the investigation is close to being finished and that authorities believe “multiple people” should be charged in connection with the “Friends” star’s death.

The source said the U.S. Attorney’s Office, which responded with “no comment” Tuesday, will decide whether to press charges.

Perry, 54, was found dead in a hot tub at his Pacific Palisades residence Oct. 28. The Los Angeles Fire Department said the actor was found unconscious in a hot tub by a bystander who had gotten Perry’s head above water while waiting for medical personnel to arrive. Once at the home, firefighters quickly pulled Perry from the water, but a rapid medical assessment revealed he died before first responders got there.

Criminal defense attorney Cori Ferrentino, who represented the drug dealer involved in Mac Miller’s overdose death, joined NewsNation’s “Banfield” to discuss the supply chain behind deadly drugs.

“What really changed, before the Mac Miller case, is they moved these prosecutions from state to federal court. In state court, they were trying to prosecute these individuals on a murder theory, and they were having trouble proving intent to kill,” Ferrentino said. “So they moved most of them to federal court, where they only have to prove conspiracy to distribute a controlled substance. But if it results in death, there’s a mandatory minimum of 20 years. That’s what my client was facing.”

How did Matthew Perry die?

Los Angeles County released the Perry autopsy, with cause of death determined to be a result of the acute effects of ketamine, Senior Deputy Medical Examiner Raffi Djabourian said.

The autopsy details trace amounts of ketamine were detected in the actor’s stomach. He was reported to be receiving ketamine infusion therapy for depression and anxiety.

Ketamine is a dissociative anesthetic with medical and surgical uses. It’s also known for recreational drug use due to its “dissociative” nature.

According to the report, toxicology testing revealed ketamine levels at 3540 ng/ml and 3271 ng/ml in Perry’s blood. For context, the medical examiner’s office said in a surgical setting, levels for general anesthesia are typically in the 1000-6000 ng/ml ranges.

The report determined Perry’s official cause of death to be from “the acute effects of ketamine,” with contributing factors including drowning, coronary artery disease and buprenorphine effects. Buprenorphine is used to treat opioid use disorder.

The manner of Perry’s death is described as “accident (drug and drowning related.)”

“At the high levels of ketamine found in his postmortem blood specimens, the main lethal effects would be from both cardiovascular overstimulation and respiratory depression. Drowning contributes,” the report said.

NewsNation’s Caitlyn Shelton contributed to this report.