The personal assistant who injected Matthew Perry with ketamine several times with no medical training, including on the day the Friends actor was found dead in a hot tub at his Los Angeles residence, was sentenced to three years and five months in prison on Wednesday.

Kenneth Iwamasa, 61, had pleaded guilty to distributing ketamine that resulted in death or serious bodily injury. The sentence handed down to him matched what prosecutors requested.

Iwamasa’s sentencing caps the criminal investigation into the five people authorities say played a role in Perry’s overdose death in 2023.

The lengthiest sentences were handed down to Jasveen Sangha, a drug dealer dubbed the “Ketamine queen” for her prolific criminal enterprise, who supplied the fatal dose, and Perry’s acquaintance, Erik Fleming, the drug addiction counselor who served as a middleman in the sale. Sangha will serve 15 years in prison while Fleming is expected to spend two years behind bars.

Salvador Plasencia, a former doctor, who continued to supply Iwamasa with ketamine after Perry had an adverse reaction – more than two weeks before his death – which left him mute and immobile, was sentenced to 30 months in prison. Another doctor, Mark Chavez, who sold ketamine to Perry, will not face prison time. Chavez was sentenced in December to eight months of home detention and three years of supervised release.

Iwamasa’s case had drawn sympathy from some Hollywood insiders, who characterized the relationship between a celebrity and their assistant as a stark power imbalance.

He “could not ‘simply say no’”, Iwamasa’s attorneys reportedly wrote in a recent court filing.

From 2022 to 2023, Iwamasa was employed as Perry’s live-in personal assistant. The two had been acquainted for more than two decades.

Perry, who had publicly shared his struggles with opioid addiction, enlisted Iwamasa’s help in the fall of 2023 to procure ketamine – an anesthetic only legal when prescribed, and which can bring on mind-altering effects, including a sedated state.

Perry had sought ketamine infusion therapy at a California clinic to treat anxiety and depression, but turned to outside sources to increase his dosage of the drug, according to federal authorities.

Prosecutors said Iwamasa paid Plasencia at least $55,000 to purchase ketamine on several occasions from September to October 2023. He also was connected to the drug via Fleming.

In the three days leading up to Perry’s death, Iwamasa injected the actor with six to eight shots of ketamine per day, according to court documents. Authorities say Iwamasa had found Perry unresponsive that month at least twice.

In letters to the judge, Perry’s family condemned Iwamasa’s behavior.

The actor’s mother, Suzanne Morrison, said the family trusted Iwamasa to help Perry remain sober. She said: “Kenny knew, should he feel unduly pressured, that with one phone call to any number of the people in Matthew’s orbit, reinforcements would be on the way.”

Perry’s sister, Madeline Morrison, recounted the days after her brother’s death, when she observed Iwamasa behave in an “unsettled” manner. “He repeatedly volunteered his version of events without being asked, as if he were being interviewed rather than mourning a friend,” she said.

“At the time, I told myself he was simply in shock, grieving as we all were. In reality, he was trying to distract us from the truth: that he had injected my brother with a lethal dose of ketamine and left him in a hot tub to die.”