Matthew Perry joked in his 2022 memoir that the drug ketamine may as well have been called "Matty," that's how seemingly made for him it was.

A quip that is nothing but tragic in hindsight.

Perry died Oct. 28, 2023, at his Pacific Palisades home from acute effects of ketamine, as determined by the Los Angeles County medical examiner. His live-in assistant found the actor unresponsive in his swimming pool hot tub, and drugs and drowning were cited as contributing factors to his death in the postmortem report.

The loss was sad from every angle, not least because Perry was only 54 and beloved by fans, most notably for his role as Chandler Bing on Friends. But also because he'd previously managed to survive a battle with substance abuse that he admitted nearly killed him on multiple occasions.

"At this point in my life, the words of gratitude pour of of me because I should be dead," Perry wrote in his book, "and yet somehow I am not."

He also wrote that, while at one point in 2020 he was getting daily ketamine infusions, he eventually decided it wasn't for him, that the "giant exhale" it provided wasn't worth how he felt afterward. 

Ketamine, which is a medical-grade anesthetic, was once known primarily as a recreational drug people took to check out or stimulate hallucinations. But it's acquired more mainstream cachet in recent years as an off-label treatment for conditions such as depression and chronic pain.

Which at first very much appealed to Perry.

Taking it was "like being hit in the head with a happy shovel," he described in the book, but "the hangover was rough and outweighed the shovel."

Yet when he died, the amount of ketamine found in his blood was equivalent to someone under general anesthesia, according to the medical examiner's autopsy report.

How Perry got his hands on that much ketamine soon became a matter for authorities, the Los Angeles Police Department confirming in May that a criminal investigation was ongoing with assistance from the Drug Enforcement Administration and U.S. Postal Service.

And just a few days before Perry would have turned 55 on Aug. 19, authorities revealed that five people—including two doctors and the assistant who found him in the hot tub—had been charged in connection with his death. 

The months-long investigation "revealed a broad underground criminal network responsible for distributing large quantities of ketamine to Mr. Perry and others," U.S. Attorney Martin Estrada said at an Aug. 15 press conference announcing the charges. "This network included a live-in assistant, various go-betweens, two medical doctors and a major source of drug supply known as, quote, the 'Ketamine Queen.'" 

Read on for all the details on the extensive legal fallout from Perry's death:

Who has been charged in connection with the death of Matthew Perry?

Jasveen Sangha, an alleged drug dealer dubbed the "Ketamine Queen," and Dr. Salvador Plasencia, a.k.a. "Dr. P," have been charged with one count apiece of conspiracy to distribute ketamine, authorities announced Aug. 15 after both were arrested.

Sangha, 41, is also charged with one count of maintaining a drug-involved premises, one count of possession with intent to distribute methamphetamine, one count of possession with intent to distribute ketamine and five counts of distribution of ketamine, according to the U.S. Attorney's Office for the Central District of California.

The superseding indictment alleges that Sangha's distribution of ketamine on Oct. 24, 2023, resulted in Perry's death. "The statutory maximum she faces is life imprisonment," prosecutor Estrada told reporters.

Sangha pleaded not guilty at arraignment in federal court and is being held without bail, according to the Associated Press. Her attorney, per the AP, didn't comment after court but did derisively refer to his client's "media-friendly nickname" in speaking on her behalf.

In addition to the conspiracy charge, Plasencia, 42, is facing seven counts of distribution of ketamine and two counts of altering and falsifying documents or records related to the federal investigation.

He's facing a maximum of 120 years in prison, Estrada said, up to 10 years per ketamine-related charge and 20 years for each records count.

Plasencia has pleaded not guilty and a judge set his bond at $100,000, per the Associated Press.

His attorney Stefan Sacks said after the hearing, per the AP, "Ultimately, Dr. Plasencia was operating with what he thought were the best of medical intentions" and his actions "certainly didn't rise to the level of criminal misconduct."

The lawyer added, "His only concern was to give the best medical treatment and to do no harm. Unfortunately harm was done. But it was after his involvement."

Three others were charged separately and plea deals are in the works, according to prosecutors.

Eric Fleming, 54, pleaded guilty on Aug. 8 to one count of conspiracy to distribute ketamine and one count of distribution of ketamine resulting in death, according to prosecutors. Per the indictment, he admitted to obtaining ketamine from Sangha and distributing it to Perry by way of the actor's assistant, Kenneth Iwamasa.

Fleming is facing up to 25 years in prison, according to the U.S. Attorney's Office.

On Aug. 7, Iwamasa pleaded guilty to one count of conspiring to distribute ketamine causing death. Per the superseding indictment, the 59-year-old admitted to repeatedly injecting Perry with ketamine—including multiple injections the day he died—without medical training. He's facing up to 15 years in prison.

Meanwhile, Dr. Mark Chavez, 54, who used to run a ketamine clinic in San Diego, Calif., is due to be arraigned Aug. 30 pursuant to an agreement to plead guilty to one count of conspiracy to distribute ketamine, according to prosecutors.

Per the indictment, he admitted to selling ketamine diverted from his own clinic—as well as obtaining additional ketamine under false pretenses from a wholesale distributor—to transfer to Plasencia.

Chavez is facing up to 10 years in federal prison.

E! News reached out to attorneys for Sangha, Iwamasa, Plasencia, Chavez and Fleming for comment but has not yet heard back.

How did the defendants get involved with Matthew Perry?

While ketamine has "some legitimate uses," Estrada told reporters, it must be administered by medical professionals "and the patient must be monitored closely. That did not occur here."

When Perry "fell back into addiction" in the fall of 2023, the prosecutor continued, the defendants "took advantage to profit for themselves."

According to authorities, Plasencia found out that Perry was interested in obtaining ketamine and worked with Chavez to get approximately 20 vials of the drug to the actor in September and October in exchange for $55,000.

Plasencia wrote in September 2023 text messages to Chavez, "I wonder how much this moron will pay" and "Lets [sic] find out," according to the indictment detailing charges against Plasencia and Sangha.

But it was Sangha, prosecutors allege, who supplied the batch of ketamine that resulted in Perry's death. In a subsequent search of Sangha's home, Estrada said, investigators found "what amounted to a drug-selling emporium," including 79 vials of ketamine, "thousands of pills," cocaine, bottles of Xanax and other illegally obtained prescription drugs, and paraphernalia including scales and ledgers that indicated an intent to sell drugs.

The defendants used coded language to discuss ketamine, Estrada said, calling it "Dr. Pepper." And after Perry died, he continued, Sangha texted Fleming and instructed him to delete all of their messages.

Plasencia later falsified medical records and notes "to make it look like what he was doing was legitimate," Estrada said. "It was not."

Noting that his office was sending a "clear message" by filing these charges, Estrada added, "Every victim's life counts. If you are in the drug-selling business and you're selling dangerous drugs, you are playing roulette with other people's lives, just like the five defendants here did to Mr. Perry."

Why was Matthew Perry taking ketamine?

Despite his professed aversion to the hangover it caused, as he detailed in his memoir, police say Perry sought treatment for anxiety and depression at an L.A.-area clinic and ended up addicted to intravenous ketamine.

"When clinic doctors refused to increase his dosage," LAPD Chief Dominic Choi said during the Aug. 15 press conference, "he turned to unscrupulous doctors who saw Perry as a way to make quick money."

Perry was charged $2,000 for a vial of ketamine that cost Chavez "approximately $12" to procure, the chief said. Wanting it "faster and cheaper" as his addiction intensified, Choi continued, Perry turned to "street dealers" who sold the stuff that "ultimately led to his death."

How did the ketamine get to Matthew Perry?

Upon finding out in late September 2023 that Perry was interested in obtaining ketamine, Plasencia contacted Chavez to get the drug to sell to the actor, according to the federal indictment unsealed by prosecutors.

The indictment alleges the doctors conspired about inventory, price and availability. Chavez then wrote a false prescription in a patient's name to obtain ketamine lozenges to sell to Plasencia and lied to wholesale distributors to buy additional vials of liquid ketamine, according to prosecutors. 

Plasencia sold ketamine to Iwamasa and Perry in September and October 2023 on at least seven occasions and taught Iwamasa—who didn't have medical training—how to inject Perry with the drug, the indictment alleges. 

Plasencia also gave Perry injections—including once inside a car in a Long Beach parking lot—without observing appropriate safety protocols, prosecutors allege in the indictment.

In mid-October 2023, Iwamasa started getting ketamine for his boss from Fleming, who procured it from Sangha, who had been dealing ketamine and other drugs out of her North Hollywood stash house since at least 2019, the indictment further alleges.

Overall, prosecutors allege, Sangha sold Perry roughly 50 vials of ketamine last October for $11,000. 

Who administered ketamine to Matthew Perry the day he died?

On Oct. 24, 2023, Fleming obtained 25 vials of ketamine, as well as an "add on" of ketamine lollipops, from Sangha and delivered them to Iwamasa at Perry's house, according to the indictment detailing charges against Sangha and Plasencia. That day, Iwamasa injected Perry with ketamine at least six times, per the charges.

Iwamasa also gave Perry at least six shots each day on Oct. 25, Oct. 26 and Oct. 27, the indictment alleges, and then—using syringes supplied by Plasencia—gave the actor at least three shots on Oct. 28, the day Perry died.

Iwamasa has admitted to giving Perry ketamine injections and administering multiple doses to him on Oct. 28, 2023, according to the indictment.

"Matthew Perry’s journey began with unscrupulous doctors who abused their position of trust because they saw him as a payday, to street dealers who gave him ketamine in unmarked vials," Drug Enforcement Administration Administrator Anne Milgram told reporters Aug. 15.

Added prosecutor Estrada, "These defendants were more interested in profiting off Mr. Perry than caring about his well-being."

“We were and still are heartbroken by Matthew’s death, but it has helped to know law enforcement has taken his case very seriously," his family—including his stepfather since 1981, Dateline host Keith Morrison—said in a statement in response to the announced charges. "We look forward to justice taking its course and we’re grateful for the exceptional work of the multiple agencies whose agents investigated Matthew’s death. We're hoping unscrupulous suppliers of dangerous drugs will get the message."