A prosecutor says five people have been charged in connection with Matthew Perry's death, including the actor's assistant and two doctors. 

U.S. Attorney Martin Estrada announced the charges Thursday, saying the doctors supplied Perry with a large amount of ketamine and even wondered in a text message how much the former Friends star would be willing to pay.

"These defendants took advantage of Mr. Perry's addiction issues to enrich themselves. They knew what they were doing was wrong," Estrada said.

Los Angeles police said in May that they were working with the U.S. Drug Enforcement Administration and the U.S. Postal Inspection Service with a probe into why the 54-year-old actor had so much of the surgical anesthetic in his system.

An assistant found Perry face down in his hot tub on Oct. 28, and paramedics who were called immediately declared him dead.

His autopsy, released in December, found that the amount of ketamine in his blood was in the range used for general anesthesia during surgery.

The decades-old drug has seen a huge surge in use in recent years as a treatment for depression, anxiety and pain. People close to Perry told coroner's investigators that he was undergoing ketamine infusion therapy.

But the medical examiner said Perry's last treatment 1½ weeks earlier wouldn't explain the levels of ketamine in his blood. The drug is typically metabolized in a matter of hours. At least two doctors were treating Perry, a psychiatrist and an anesthesiologist who served as his primary care physician, the medical examiner's report said. No illicit drugs or paraphernalia were found at his house.

Ketamine was listed as the primary cause of death, which was ruled an accident with no foul play suspected, the report said. Drowning and other medical issues were contributing factors, the coroner said.

Perry had years of struggles with addiction dating back to his time on Friends, when he became one of the biggest television stars of his generation as Chandler Bing, alongside Jennifer Aniston, Courteney Cox, Lisa Kudrow, Matt LeBlanc and David Schwimmer for 10 seasons from 1994 to 2004 on NBC's mega-hit sitcom.