A 53-year-old anesthesiologist who worked at a medical office in Beverly Hills has been charged with murder following the death of a patient in September.

Stephen Kyosung Kim, a licensed physician, pleaded not guilty to the murder charge on Dec. 14 and was ordered to return on Jan. 25 for a preliminary hearing.

The charge stems from an investigation into the death of a 71-year-old man on Sept. 26 at Rodeo Plastic Surgery, 421 N. Rodeo Drive.

Authorities received a 911 call about a patient not breathing. Paramedics arrived and attempted life-saving resuscitation, but the man died at the scene.

The victim was identified as Mark Greenspan. Police were told the victim stopped breathing during recovery from a surgery earlier that day.

The incident was investigated by the Beverly Hills Police Department, the Medical Board of California and the Los Angeles County District Attorney’s Office. Authorities allege Kim gave Greenspan a lethal dose of the sedative Demerol while he was in the recovery room. Authorities also allege that Kim injected himself and was under the influence of narcotics during the surgery.

The type of narcotic Kim allegedly used, and the type of surgery Greenspan was undergoing, were not disclosed because of the pending court proceedings.

Kim turned himself into police on Dec. 14. After pleading not guilty, he posted $1 million bail and remains free pending further court proceedings.