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

As medical examiners began an autopsy on 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.

KPRC Local 2 identified the doctor as Dr. Conrad Murray.

Police said they wanted to question the doctor about the medication Jackson was taking prior to his death.

Rayner stressed the doctor was not under criminal investigation.

Murray is not only licensed in Texas, he was founder of the Acres Homes Heart and Vascular Institute, located at 509 W. Tidwell Road. He also had privileges at Doctor's Hospital Tidwell.

Police said the BMW towed from Jackson's home is actually registered to Murray's sister, who lives in southwest Houston. Houston police tried to notify her that Los Angeles police detectives would like to speak to her, but she did not appear to be home.

Conrad Murray also practiced at Global Cardiovascular Associates in Las Vegas and in California.

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.

Jackson's autopsy began Friday morning and was expected to last several hours. An official determination on cause of death was not expected for six or eight weeks, 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 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.

Jackson died after being stricken at his rented home in the posh Los Angeles neighborhood of Holmby Hills. Paramedics tried to resuscitate him for three-quarter of an hours there before rushing him to the hospital.

His brother Jermaine said Jackson apparently suffered cardiac arrest, an abnormal heart rhythm that stops the heart from pumping blood to the body. It can occur after a heart attack or be caused by other heart problems.

Jackson was preparing for a monster comeback bid -- a series of 50 concerts that was to begin next month in London.

Jackson's death brought a tragic end to a long, bizarre, sometimes farcical decline from his peak in the 1980s, when he was popular music's premier all-around performer. His 1982 album "Thriller" -- which included the blockbuster hits "Beat It," "Billie Jean" and "Thriller" -- is the best-selling album of all time worldwide.

Yet after selling more than 61 million albums in the U.S. and having a decade-long attraction open at Disney theme parks, Jackson died reportedly awash in about $400 million in debt, on the cusp of a final comeback after well over a decade of scandal.

The public first knew Jackson as a boy in the late 1960s, when he was the precocious, spinning lead singer of the Jackson 5, the singing group he formed with his four older brothers out of Gary, Ind. Among their No. 1 hits were "I Want You Back," "ABC" and "I'll Be There."

He was perhaps the most exciting performer of his generation, known for his backward-gliding moonwalk, his feverish, crotch-grabbing dance moves and his high-pitched singing, punctuated with squeals and titters. His single sequined glove, tight, military-style jacket and aviator sunglasses were trademarks, as was his ever-changing, surgically altered appearance.

Jackson ranked alongside Elvis Presley and the Beatles as the biggest pop sensations of all time. He united two of music's biggest names when he was briefly married to Presley's daughter, Lisa Marie. Jackson's sudden death immediately evoked comparisons to that of Presley himself, who died at age 42 in 1977.

As years went by, Jackson became an increasingly freakish figure -- a middle-aged man-child weirdly out of touch with grown-up life. His skin became lighter, his nose narrower, and he spoke in a breathy, girlish voice. He often wore a germ mask while traveling, kept a pet chimpanzee named Bubbles as one of his closest companions and surrounded himself with children at his Neverland ranch, a storybook playland filled with toys, rides and animals. The tabloids dubbed him "Wacko Jacko."

After the enormous success of "Thriller," Jackson had strong follow-up albums with 1987's "Bad" and 1991's "Dangerous," but his career began to collapse in 1993 after he was accused of molesting a boy who often stayed at his home.

The singer denied any wrongdoing, reached a settlement with the boy's family, reported to be $20 million, and criminal charges were never filed.

Jackson caused a furor in 2002 when he playfully dangled his infant son, Prince Michael II, over a hotel balcony in Berlin while a throng of fans watched from below.

In 2005, he was cleared of charges that he molested a 13-year-old cancer survivor at Neverland in 2003. He had been accused of plying the boy with alcohol and groping him, and of engaging in strange and inappropriate behavior with other children.

The case followed years of rumors about Jackson and young boys. In a TV documentary, he acknowledged sharing his bed with children, a practice he described as sweet and not at all sexual.

Despite the acquittal, the lurid allegations that came out in court took a fearsome toll on his career and image, and he fell into serious financial trouble.

Jackson married Lisa Marie Presley in 1994, and they divorced in 1996. Later that year, Jackson married Deborah Rowe, a former nurse for his dermatologist. They had two children together: Michael Joseph Jackson Jr., known as Prince Michael, now 12; and Paris Michael Katherine Jackson, 11. Rowe filed for divorce in 1999.

Jackson also had a third child, Prince Michael II, now 7. Jackson said the boy, nicknamed Blanket as a baby, was his biological child born from a surrogate mother.

Jackson's 13 No. 1 one hits on the Billboard charts put him behind only Presley, the Beatles and Mariah Carey.