Detectives investigating the death of Michael Jackson are looking at his prescription drug history and trying to talk with his numerous former doctors, the Los Angeles police chief said Thursday.

Chief William Bratton told CNN that police are waiting for the coroner's report before ruling out any possibilities in their "comprehensive and far-reaching" investigation into the sudden death of the 50-year-old pop star two weeks ago.

The coroner's report will determine the cause of death and hinges on time-consuming toxicology tests.

"Based on those we'll have an idea of what we're dealing with," Bratton said. "Are we dealing with homicide? Are we dealing with an accidental overdose? What are we dealing with?"

PHOTOS: Click for scenes from the Jackson memorial

Bratton said detectives are gathering evidence, including items seized from Jackson's rented home and arranging interviews with his many physicians, but the police chief deferred to the coroner to determine the cause of death.

"The next move really is his," Bratton said. "We're not marking time waiting for his report."

The Drug Enforcement Agency and the state attorney general's office, which keeps a database of prescription drugs, are assisting investigators.

An attorney for Dr. Arnold Klein, one of Jackson's many physicians, told the Los Angeles Times that the dermatologist was subpoenaed for medical records, which he turned over to the county coroner's office.

Bratton refused to discuss details of the case.

Jackson, who died June 25, had a well-known history of using prescription medications, especially painkillers. Following his death, Cherilyn Lee, a registered nurse who had worked for Jackson, told the Associated Press she repeatedly rejected his demands for the potent anesthetic Diprivan, also known as Propofol.

Jackson had multiple doctors, friends and staff who came in and out of his life. Which people were being interviewed by police was unclear because the LAPD has said virtually nothing about the probe.

Police towed a doctor's car from Jackson's home hours after he died and said later it could contain medication or other evidence. Coroner's officials also said Jackson was taking prescription medication but declined to elaborate.

Click here for all of FOXNews.com's coverage of Michael Jackson.