Lagos — The head of the Los Angeles Police, William Bratton yesterday told CNN that detectives were investigating late music icon, Michael Jackson's history of using prescription drugs and had spoken to a number of doctors who had treated him over the years.

"At the time of the death, with search warrants, we were able to seize a number of items from the residence where the death occurred and those will assist in the investigation.

"We are still awaiting corroboration from the coroner's office as to the cause of death. That is going to be very dependent on the toxicology reports that are due to come back. Based on those, we will have an idea of what it is we are dealing with," he said.

Bratton said his department was being helped by other agencies, including the Drug Enforcement Administration, on "a comprehensive set of inquiries."

Bratton also refused to rule out murder in the investigation into the death of the singer two weeks ago.

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

Meanwhile, Jackson's father, Joe, 79, speaking about the death on ABC News yesterday said: "I do believe it was foul play."

Jackson's father had previously said he had "a lot of concerns" over events surrounding his son's death, and that the family "suspected foul play somewhere."

The Los Angeles coroner has said that an autopsy the day after the singer's death revealed no evidence of foul play and that toxicology test results could take weeks to come back.

A spokesman for the coroner's office said Jackson had taken "some prescription medication," without specifying which.

Meanwhile, the makers of the British West End tribute show, Thriller Live, are taking the show on a year-long world tour.

The musical, which began as a touring show in 2006, has been showing at London's Lyric Theatre since January.

A new production of the show will be staged in Munich, Germany on 21 July, before travelling across Europe and on to the US.

"Since the tragic news from Los Angeles broke, we have been amazed by the reaction of the fans around the globe, and inquiries for Thriller Live to appear worldwide have been overwhelming," producer Paul Walden said.