The authorities in Los Angeles have made an arrest as part of their investigation into the death of Matthew Perry, according to two people with knowledge of the inquiry.

The authorities, who have been trying to find out who supplied the ketamine that was in Perry’s system when he was found dead in a hot tub last October at his Los Angeles home, arrested a woman named Jasveen Sangha in connection with the case, according to the two people, who were granted anonymity to discuss an ongoing investigation. More details, including the roles played by others in the case, are expected to be released at a news conference in Los Angeles on Thursday morning.

The Los Angeles County medical examiner’s office said in an autopsy report released in December that Mr. Perry had died of “acute effects of ketamine.” The actor, who gained sitcom superstardom as Chandler Bing on the show “Friends,” was discovered “floating face down” in the heated end of a pool at his home in Los Angeles.

Ketamine, a powerful anesthetic with psychedelic properties, is increasingly being used as an alternative therapy for depression, anxiety and other mental health problems. It is also used, and abused, recreationally.

The police in Los Angeles acknowledged this year that they were working with the federal Drug Enforcement Administration to investigate the source of Mr. Perry’s ketamine and whether it was obtained legally. A spokesman for the United States Postal Inspection Service said it was assisting with the investigation.

The autopsy report said that Mr. Perry had been on ketamine infusion therapy, but it determined that the ketamine in his system could not have been from his last known therapy session, about a week and a half before he died. The autopsy said the level of ketamine found in Mr. Perry’s blood was equivalent to the amount that would be used during general anesthesia.

Mr. Perry had a history of drug and alcohol addiction, which he wrote about in a memoir.

The medical examiner’s office said that drowning, coronary artery disease and buprenorphine, which is used to treat drug addiction and for pain, had contributed to his death.

Glenn Thrush contributed reporting from Washington.