LOS ANGELES — Police investigating Michael Jackson's death looked into his medical treatment Friday, seeking to interview one of the pop king's doctors and seizing a car that they said may contain drugs or other evidence.

As medical examiners began an autopsy for Jackson, police towed a BMW from rented home "because it may contain medications or other evidence that may assist the coroner in determining the cause of death," police spokeswoman Karen Rayner said.

She said the car belongs to one of Jackson's doctors whom police wanted to interview. Rayner said she did not know the doctor's identity and stressed the doctor was not under criminal investigation.

The autopsy began Friday morning and was expected to last several hours. An official determination on cause of death was not expected for weeks or longer, until more sophisticated tests are completed.

In a 911 call released by fire officials, a caller reports Jackson was on a bed and not breathing or responding to CPR. The unidentified caller said Jackson only was with his personal doctor at the time.

"I need an ambulance as soon as possible, sir," the caller said urgently but politely. "We have a gentleman here that needs help and he's not breathing yet. He's not breathing and we need to — we're trying to pump him, but he's not, he's not."

The pop star died later Thursday afternoon at UCLA Medical Center.

As stores reported they were inundated with orders for Jackson's music, a chorus of grief for the megastar spread around the world, from statesmen to icons of music to legions of heartbroken fans.

"I can't stop crying. This is too sudden and shocking," said Diana Ross, who helped launch Jackson's career. "I am unable to imagine this. My heart is hurting."

Lisa Marie Presley, briefly married to the pop icon in the mid-1990s, said he had confided to her 14 years ago that he worried about facing the same tragic fate as her father, Elvis Presley, who died of a drug overdose at age 42.

"The world is in shock but somehow he knew exactly how his fate would be played out some day more than anyone else knew, and he was right," she wrote in a long, emotional statement on her MySpace page online.

The White House also weighed in for the first time, with a spokesman saying President Barack Obama saw Jackson as a spectacular performer and music icon whose life nonetheless had sad and tragic aspects. The House of Representatives observed a moment of silence.

Brian Oxman, a former Jackson attorney and a family friend, said Friday he had been concerned about Jackson's use of painkillers and had warned the singer's family about possible abuse.