Matthew Perry, who played Chandler Bing in the hit US sitcom Friends, died on 28 October last year from the "acute effects of ketamine" at the age of 54.
An investigation unearthed a "broad underground criminal network" of people who "took advantage" of the US actor after he fell back into addiction in the autumn of last year.
The first of five people charged over his death will be sentenced on Wednesday.
Erik Fleming pleaded guilty on 8 August to conspiracy to distribute ketamine and distribution of ketamine resulting in death.
During the last few weeks of his life, Perry "turned to street dealer" Fleming who is said to have sourced ketamine from Jasveen Sangha – named by authorities as "the ketamine queen".
The ketamine allegedly supplied by Sangha was ultimately the dose that took Perry’s life, a Drug Enforcement Administrator claimed.
Sangha is to face a trial on 4 March next year, alongside Salvador Plasencia, a doctor who allegedly used Perry’s live-in assistant Kenneth Iwamasa to distribute ketamine to the actor from September to October last year.
Iwamasa pleaded guilty on 7 August to conspiring to distribute ketamine causing death – admitting to "repeatedly injecting Perry with ketamine without medical training" – with his sentencing set for 6 November.
Meanwhile, another doctor named Mark Chavez became the last defendant to admit to conspiring to distribute the surgical anaesthetic ketamine following the death of Perry.
His sentence hearing was scheduled for 2 April 2025.
Perry had been seeking treatment for depression and anxiety when he became addicted to intravenous ketamine, turning to allegedly "unscrupulous doctors who saw Perry as a way to make quick money", US attorney Martin Estrada said.
Ketamine is a sedative that can be used as a recreational drug, as well as to treat depression and pain management.
Perry was open about his battle with substance abuse and addiction, setting up a sober living facility for men with similar issues.
After his death, a foundation was set up in his name to help those struggling with addiction.
His mother Suzanne Morrison recently said Perry appeared to have a "premonition" about his death on one of the last times they spoke.
In an interview with NBC’s morning talk show Today to mark the anniversary of his death, Ms Morrison said: "He came up to me and said, 'I love you so much and I’m so happy to be with you now’.
"It was almost as though it was a premonition or something. I didn’t think about it at the time but I thought, ‘How long has it been since we’ve had a conversation like that? It’s been years’."
Ms Morrison added: "I think there was something… there was an inevitability to what was going to happen next to him, and he felt it very strongly.
"But he said, ‘I’m not frightened any more’. And it worried me."
Source: Press Association
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