Authorities have arrested at least one person in connection with the ketamine overdose death of Matthew Perry last year, a law enforcement official told The Associated Press.

The official was not authorized to discuss details of an ongoing investigation and spoke to the AP on condition of anonymity. Authorities have scheduled a news conference in Los Angeles to announce details of the case on Thursday morning.

Los Angeles police said in May that they were working with the U.S. Drug Enforcement Administration and the U.S. Postal Inspection Service to investigate why the 54-year-old man had such a high amount of surgical anesthetic in his body.

On Oct. 28, a deputy found Perry lying face down in a hot tub, and paramedics who were called immediately pronounced him dead.

His autopsy report, released in December, found the amount of ketamine in his blood was equal to the amount used for general anesthesia during surgery.

Use of the decades-old drug has surged in recent years as a treatment for depression, anxiety and pain. People close to Perry told coroner’s investigators that he had been undergoing ketamine infusion therapy.

But the medical examiner said Perry’s last treatment 1 1/2 weeks ago could not explain the level of ketamine in his blood. The drug is typically metabolized within a few hours. The medical examiner’s report said Perry was treated by at least two doctors, a psychiatrist and an anesthesiologist who served as his primary care physician. No illegal drugs or paraphernalia were found at his home.

The report said ketamine was cited as the primary cause of death, which was ruled an accident with no foul play suspected. The coroner said drowning and other medical issues caused the death.

Perry has struggled with addiction for years, dating back to his time on “Friends,” when he became one of the biggest television stars of his generation as Chandler Bing alongside Jennifer Aniston, Courteney Cox, Lisa Kudrow, Matt LeBlanc and David Schwimmer on NBC’s megahit sitcom for 10 seasons from 1994 to 2004.