King of Pop Michael Jackson is generating as much controversy and speculation in death as the eccentric entertainer did in life.

A number of publications world-wide are reporting that UCLA emergency room staff have said Jackson’s aides told medics he had collapsed after an injection of Demerol — a powerful pain killer similar to morphine.

According to the English newspaper The Sun, “shortly after taking the Demerol he started to experience slow shallow breathing. His breathing gradually got slower and slower until it stopped.

“His staff started mouth-to-mouth and an ambulance was called which got there in eight minutes, but found he was in full respiratory arrest, no breathing and no pulse. They started full CPR and rushed him to hospital.

“When he arrived [at the hospital] they started resuscitation, giving him heart shocks and inserted a breathing tube and other supportive measures to try and save his life. He never regained consciousness.”

A Los Angeles City Fire Department spokesman said, “when the team arrived, they saw that CPR was already in progress by someone at the home. The person not breathing was transported to UCLA Medical Centre.”

Jackson had been blighted by a string of past health problems — including rumoured heart trouble, and the recent discovery of skin cancer on his upper body and pre-cancerous cells on his face.

It has been reported that Jackson’s personal doctor was with him at the time he went in to cardiac arrest but at this stage it is not clear who administered the Demerol, or if in fact it was administered at all.

The Los Angeles Police Department’s homicide division is leading an inquiry into the star’s death, with his friends, family and associates to be interrogated by detectives, and the city coroner to conduct a formal inquest.

Demerol is a narcotic painkiller similar to Morphine that is used to treat moderate to severe pain. Though successful as a pain reliever, Demerol’s side effects include thought impairment, slowed reactions, and death if taken in excess. It is also known to be addictive.