Matthew Perry death investigation: Legal experts weigh in on ketamine charges, why doctors' and assistant's involvement is key

News that arrests were made in Matthew Perry's death investigation reverberated through Hollywood and beyond on Thursday as five people have been charged in the actor's fatal ketamine overdose. As one lawyer tells Yahoo Entertainment, this case "has some very unusual aspects to it."

Of the five people charged, two are doctors, one was Perry's personal assistant and two are alleged drug dealers, including the so-called "Ketamine Queen" of Los Angeles. According to legal experts, the high-profile nature of the case was a driving force in the investigation.

"It's very rare to see a person [like Perry] who has such an involved network facilitating access to drugs. I don't think you get that kind of treatment unless you're very famous or very rich," L.A. health care attorney Harry Nelson, who was involved in the Perry case and investigation, explains to Yahoo. "So I do think it's unusual in that there's just not that many cases where [all investigative authorities] spend enormous resources here."

Perry was found unresponsive in the heated end of his pool on Oct. 28, 2023. A criminal investigation was launched after the Los Angeles County medical examiner's office determined Perry died due to "acute effects of ketamine." The Los Angeles Police Department, the Drug Enforcement Administration (DEA), the U.S. Postal Service and the U.S. Attorney's Office for the Central District of California all looked into Perry's death.

Nelson has been involved in several high-profile cases, including Michael Jackson’s after he died from "acute propofol intoxication" in 2009. It was ruled a homicide.

"It's very unusual that you see a federal investigation, even when it's controlled substances," he says. "It's usually local law enforcement, a local district attorney and not the federal government. This one got enormous attention because it was a national media story, and again, unusual circumstances in terms of how many people were facilitating and enabling the things that actually killed Matthew Perry."

Criminal defense lawyer Lauren Johnson-Norris agrees, telling Yahoo that while "these kinds of charges are becoming increasingly more common," there likely was "more attention due to Perry's high-profile status, which led to the charging of these individuals."

"Many substance abusers overdose, but few people around them are willing to turn over the dealers," Johnson-Norris explains. "In this case, it appears that Perry's assistant likely gave over that information. If prosecutors knew who distributed the drugs that killed people more often, I am sure they would charge more cases from overdoses."

Perry's live-in assistant, Kenneth Iwamasa, pleaded guilty to one count of conspiracy to distribute ketamine causing death. According to federal prosecutors, he admitted "to repeatedly injecting Perry with ketamine without medical training." He is accused of procuring ketamine from two drug dealers and one doctor, all of whom are among those charged. Iwamasa performed "multiple injections" on the Friends star the day Perry died.

"The interesting thing about the assistant is you have this whole network of people in Hollywood who are basically empowered to do all these things for the clients that they serve — very powerful, wealthy, famous people," Nelson says, noting that it’s not uncommon for celebrity assistants to be "involved [in] the medical care of their clients and facilitate things like medication."

Perry had been undergoing ketamine infusion therapy to treat depression and anxiety before he died, which is legal for use by registered medical practitioners. In Thursday's press conference, the DEA said he became addicted to "intravenous ketamine" in the fall of 2023.

Court documents obtained by NBC News outline Iwamasa's plea agreement and reveal details of the hours leading up to Perry's death. Iwamasa allegedly injected Perry on Oct. 28, 2023, at 8:30 a.m. and again at 12:45 p.m. while Perry was watching a movie. The actor purportedly instructed him to turn on the Jacuzzi and "shoot me up with a big one," referring to ketamine. When Iwamasa came back from running errands, he found Perry face down in the pool.

"I was aware from the investigation that they were asking questions [about Iwamasa]," Nelson, author of The United States of Opioids, reveals. "[Investigators] were subpoenaing records and wanting to know how many times he got on the phone. They wanted to see texts from him to see what his role was."

Nelson says this was "a very complicated situation with people around" Perry "who were trying to help him get what he needed medically, but obviously may have crossed the line and helped facilitate things that were questionable. It's really unusual to see somebody like Iwamasa added to this situation."

Perry's friends and family have been "blindsided" and "saddened" by Iwamasa's arrest, according to Us Weekly. But Johnson-Norris says she's "not surprised" he was charged.

"[Iwamasa] is not excused because his boss told him to commit an illegal act. He is an adult and is required to follow the law like everyone else. You also can't shoot people up with illegal drugs just because they ask you to," she explains. "It's too dangerous. In this case, it cost Perry his life."

Iwamasa allegedly worked with Dr. Salvador Plasencia in obtaining ketamine and learning how to inject the drug. Plasencia was arrested on Thursday and faces multiple counts in Perry's death. NBC News reports Plasencia told a patient that Perry was "too far gone and spiraling in his addiction" the week before the actor died, per court documents, but still offered to sell him ketamine through Iwamasa.

Dr. Mark Chavez was arrested and charged for allegedly selling Plasencia ketamine, but reached a plea agreement. Nelson says that, along with major drug dealers, doctors were a "major target" in this case because of their professional responsibilities.

Johnson-Norris adds: "We should all be shocked that doctors were involved in the illegal distribution of controlled substances to their patient. Doctors take [an] oath to do no harm, but here they were clearly taking advantage of Perry's addiction for the money. I am not surprised they were charged as a result of the conduct here, but I am surprised that they would engage in these acts because they are doctors. It is reprehensible."

Johnson-Norris believes the fact that doctors were involved is "the most significant part about this case."

"These doctors had a vulnerable patient who needed help from them with his addiction. Instead, they exploited their positions and kept him hooked on ketamine for profit. That is shocking and disturbing, and definitely an aggravating factor in this case," she says.

Although ketamine can be a safe and effective tool for mental health issues when administered properly by health care professionals, this case should serve as a major warning.

"We are seeing that ketamine is everywhere and it can be extremely dangerous when used outside of a medical context," Johnson-Norris says. "The fact it is advertised to treat mental health and addiction only compounds the problem with its potential abuse. Websites and purported online doctors and wellness centers who supply drugs like these should be more closely scrutinized to protect the public."