Los Angeles police investigating the death of Michael Jackson have yet to rule out homicide.

Chief William Bratton, who is leading the investigation, told CNN detectives were awaiting the results of toxicology tests.

"Are we dealing with a homicide or are we dealing with accidental overdose... I don't have that information,” he said.

Bratton added: "That is going to be very dependent on the toxicology reports that are due to come back.”

Jackson died on June 25 following a suspect cardiac arrest at his home in Homby Hills.

An original post-mortem ruled out foul play, but a cause of death was deferred pending the results the toxicology tests, which could take up to six weeks.

Bratton said the police investigation had now centred on Jackson's alleged use of prescription medication.

The singer is believed to have taken some prescription drugs before his death, although exactly what substances have yet to be made public.

Police have already interviewed a string of doctors who treated Jackson in recent years, including his most recent physician, Dr Conrad Murray.

US media reports had claimed Dr Murray had injected the singer with Demerol, a drug similar to morphine, shortly before his death.

But Dr Murray’s lawyer, Edward Chernoff, later told the Los Angeles Times these claims were “absolutely false”.

(by Jason Gregory)