The final sentencing in the 2 1/2-year investigation and prosecution following the drug death of Matthew Perry will be of the personal assistant who sat at the center of the entire affair, buying the ketamine that would cause the death of the “Friends” star and injecting him with the lethal dose.

Kenneth Iwamasa, 60, is set to be sentenced Wednesday in the Los Angeles federal courtroom of Judge Sherilyn Peace Garnett, who has sentenced four of his co-defendants in the past year.

He was the first of them to reach a deal with prosecutors, pleading guilty in August 2024 to one count of conspiracy to distribute ketamine resulting in death. Wednesday will be his first court appearance since the case became public knowledge.

Iwamasa became the most important witness for the prosecution. They are asking Garnett to sentence him to three years and five months in prison, significantly less than what he might have faced without cooperating, but still more than all but one of his co-defendants.

Iwamasa’s lawyers said in a court filing that he was an employee doing his employer’s bidding and had a “particular vulnerability” in his relationship to Perry. “In short, he could not ‘simply say no.’ That inability had tragic consequences.”

Perry’s family members, some of whom may speak in court, made it clear in letters to the judge that there is no one they blame for his death more than Iwamasa — a longtime friend they thought would help the actor maintain sobriety but instead indulged the worst impulses of a lifelong addict.

“Mathew trusted Kenny. We trusted Kenny. Kenny’s most important job — by far — was to be my son’s companion and guardian in his fight against addiction,” wrote Perry’s mother, Suzanne Morrison. “We trusted a man without a conscience, and my son paid the price.”

Perry had hired Iwamasa in 2022, and he was paying him $150,000 a year to live at his Los Angeles home and act as his assistant.

The actor had been taking the surgical anesthetic ketamine legally for depression, an increasingly common off-label use. But he wanted more than his doctor would give him.

According to Iwamasa’s plea agreement, he bought off-the-books ketamine from another doctor, Salvador Plasencia, who taught him how to inject it. Plasencia was sentenced to 2 1/2 years in prison in July.

Iwamasa also began buying ketamine from Perry acquaintance Erik Fleming, who was getting it from a street dealer. Fleming was sentenced to two years in prison two weeks ago.

The dealer, Jasveen Sangha, dubbed “The Ketamine Queen,” was sentenced to 15 years on April 8.

In the final days of Perry’s life, Iwamasa was injecting him six to eight times per day. On Oct. 23, 2023, he shot the 54-year-old actor full of a large dose and left to run errands. He returned to find Perry dead in the Jacuzzi.

The LA County Medical Examiner found that ketamine was the primary cause of death. Drowning was a secondary cause.

At first, Iwamasa lied to police, omitting ketamine from the list of medications Perry was using, and saying nothing about his injections.

But when investigators served a search warrant in January of 2024, he began coming clean.

Perry became one of the biggest stars of his generation along with Courteney Cox, Jennifer Aniston, Matt LeBlanc, David Schwimmer and Lisa Kudrow on “Friends,” NBC’s megahit sitcom that ran from 1994 to 2004.