LOS ANGELES - With initial autopsy results inconclusive, the investigation into Michael Jackson's sudden death focused yesterday on a financially strapped Las Vegas physician who was by the pop icon's side when he went into cardiac arrest in Los Angeles.

Detectives were to meet with Conrad Murray, a cardiologist tapped to be Jackson's personal doctor during his comeback concerts in London, yesterday afternoon amid questions about the singer's use of prescription drugs. Earlier, investigators seized Murray's BMW sedan from the driveway of Jackson's rented mansion.

"It may contain medications or other evidence that may assist the coroner in determining the cause of death," a police spokeswoman said.

Murray was performing CPR on Jackson when paramedics arrived Thursday afternoon at the residence, and he accompanied the ambulance to the hospital. In a call to 911 from inside the home, an unidentified man said Jackson, 50, was on a bed being tended by his personal doctor.

"He's not breathing. He's not breathing," the man said. "We are trying to pump him."

Jackson was pronounced dead at the University of California, Los Angeles, Medical Center.

Coroners officials completed an autopsy yesterday, but said determining the cause of death would require additional tests, including a toxicology screen that could take four to six weeks.

"We know he was taking some prescription medication," said Craig Harvey, a spokesman for the Los Angeles County Coroner's Office. He said there were no signs of foul play in the autopsy.

Investigators were also turning to Murray for information about Jackson's health and use of drugs.

Police, however, stressed that Murray was not the target of a criminal investigation.

Licensed in California, Nevada, and Texas, Murray was summoned to Los Angeles in the last two weeks at Jackson's request, said the singer's adviser, Tohme Tohme. Murray, who also had a practice in Houston, had treated Jackson for three years, including a period when he lived in Las Vegas, according to Randy Phillips, the chief executive of AEG Live, the concert promoter mounting the London shows.

"Michael told me personally that he trusted this man," Phillips said. The company was preparing to advance Murray a "significant" amount of money to be with Jackson in London through next March. He was to travel with the singer and the rest of the company early next week.

"Michael wanted a full-time physician to treat him, someone who was just his physician," Phillips said.

He said he wanted to hire a physician once they arrived in London, but Jackson "insisted emphatically that Dr. Murray be his physician."

Murray did not return messages left at his offices and no one answered the door at his Las Vegas home - a million-dollar stucco-and-stone dwelling in a gated community next to the Red Rock Country Club.

Despite the upscale residence, the 51-year-old was struggling with financial problems. He was hit with hundreds of thousands of dollars in legal judgments last year and has a history of money problems.

In 2008, three judgments were filed against Murray or his company, Global Cardiovascular Associates, in Clark County, Nev., totaling more than $435,000, and two other cases are pending from companies that say Murray owes them a total of $355,000. The three judgments include $71,332 for school loans, $135,302 to Popular Leasing USA, and $228,420 to Citicorp Vendor Finance. In addition to the recent judgments, Murray filed for bankruptcy in 1992 in Southern California's Riverside County.

The 911 call released by fire officials shed light on the desperate effort at the mansion to save Jackson's life before paramedics arrived.

In the recording, an unidentified caller pleads with authorities to send help, offering no clues about why Jackson was stricken. He tells a dispatcher that Jackson's doctor is performing CPR.

"He's pumping his chest," the caller says, "but he's not responding to anything."

Asked by the dispatcher whether anyone saw what happened, the caller answers: "No, just the doctor, sir. The doctor has been the only one there."

Jackson had remained out of the public spotlight during intense rehearsals for the London concerts, but those with access said he was upbeat and seemingly energized by his planned comeback.

Ken Ehrlich, executive producer of the Grammys, said he watched Jackson dance energetically as recently as Wednesday.

"There was this one moment, he was moving across the stage and he was doing these trademark Michael moves, and I know I got this big grin on my face, and I started thinking to myself, 'You know, it's been years since I've seen that,' " he said.

Lou Ferrigno, the star of The Incredible Hulk, said he had been working out with Jackson for the last several months.

The worldwide wave of mourning for Jackson continued unabated for the man who revolutionized pop music and moonwalked his way into entertainment legend.

"My heart, my mind are broken," said Elizabeth Taylor, who was one of Jackson's closest friends and married one of her husbands at a lavish wedding at the pop star's Neverland Ranch in 1991. She said she had heard the news as she was preparing to travel to London for Jackson's comeback show, and added, "I can't imagine life without him."

At rehearsals for tomorrow's BET Awards show, stars such as Beyonce, Wyclef Jean, and Ne-Yo were frantically revamping their performances in an effort to turn the evening into a Michael Jackson tribute.

No funeral plans had been made public.

This article includes information from the Associated Press.