LOS ANGELES - Los Angeles County coroner's spokesman Craig Harvey said yesterday determining the cause of Michael Jackson's death will require further neuropathology and pulmonary tests that will take four to six weeks.

Harvey said that during the three-hour autopsy yesterday there were no signs of foul play or trauma to the body. He also said Jackson was taking some unspecified prescription medications.

Harvey said the Police Department has requested a security hold on the investigation which limits how much the coroner's office can say about the case.

Los Angeles Police investigating Jackson's death looked into his medical treatment yesterday, 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 the autopsy on Jackson, police towed a BMW from his 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 Dr. Conrad R. Murray, one of Jackson's personal doctors. Rayner stressed that the cardiologist was not under criminal investigation.

State regulators had no records of any disciplinary actions against him.

Murray's office in Las Vegas, Global Cardiovascular Associates Inc., was locked and dark yesterday. Mary Russell, property manager for the office said she had not seen Murray all week.

A reporter who tried to visit Murray's Las Vegas home was turned away by two armed guards at the entrance to the gated community where it's located.

In a 9-1-1 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 Murray 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.

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. *