(KHOU) 11 News has learned that a Houston doctor was in Michael Jackson's Southern California home when he collapsed from sudden cardiac arrest.

A medical assistant at the Acres Home Heart and Vascular Institute confirmed that Dr. Conrad Robert Murray, a cardiologist licensed to practice medicine in Texas and Nevada, was living with Michael Jackson at his rented Holmby Hills mansion.

She said Dr. Murray was with Jackson at the time he suffered cardiac arrest Thursday afternoon.

“I need an ambulance as soon as possible,” the person who called 911 told the dispatcher. “We have a gentleman here who needs help. He’s not breathing.”

Jermaine Jackson said his brother's personal physician tried to resuscitate him at his home.

The person who called 911 when Jackson collapsed confirmed that.

“He’s pumping, he’s pumping his chest but he’s not responsive," the caller said.

The Los Angeles Times reported Friday that it was Murray who was performing CPR when paramedics arrived at the entertainer’s home Thursday.

Doctors at the hospital tried to revive Jackson for more than an hour, but were unsuccessful.

Police towed the car of a doctor from Jackson’s rented mansion Friday.

“His car was impounded because it may contain medications or other evidence that may assist the coroner in determining the cause of death,” Los Angeles police spokeswoman Karen Rayner.

11 News has learned the towed BMW had Texas license plates that are registered to Susan Rush, who is Dr. Murray's sister, according to the medical assistant.

Rush also worked for Murray at one of his clinics.

The Texas State Board of Medical Examiners Web site shows no complaints filed against Murray in the four years he’s been a licensed cardiologist in Texas.