LONDON - Tests have confirmed that King of Pop Michael Jackson had a cocktail of powerful painkiller Demerol and heroin substitute methadone in his body when he died.

According to reports, the drugs found in the star’s body were strong enough to have killed any normal person instantly. reliminary toxicology reports have been submitted to the Los Angeles county coroner’s office.

The revelation of their findings came as sources predicted that Jackson’s death could result in manslaughter or even murder charges.

“Michael Jackson was a walking drug store when he died - he never stood a chance,” the Sun quoted a case insider as saying.

The newspaper report says that apart from high levels of Demerol and Methadone, blood tests also revealed high levels of anti-anxiety drug XANAX in the singer’s body.

It further states that lower levels of Propofol, an anaesthetic for hospital use only, were also present in the ‘Thriller’ hitmaker’s body.

A significant amount of narcotic Dilaudid, normally used to numb post-surgery pain, was discovered, added the report.

Another post-op painkiller called Fentanyl was also found in “therapeutic” levels. This is known to be 100 times more potent than morphine.

Tests have also confirmed the presence of prescription painkiller Vicodin, anti-anxiety pills Valium and the sleeping drug Ambien in Jackson’s body.

“The body can build up extreme tolerances to huge doses of drugs but eventually it overloads and just shuts down. That is what happened to Michael,” the insider said.

“Tests showed that as well as Demerol and methadone, he had taken four more painkillers and anaesthetics plus anti-anxiety pills.

“This is sure to increase pressure on police to establish exactly how one man obtained so many prescription medications - and which doctors were responsible.

“There is increasing talk of manslaughter charges if it can be shown he was given drugs without proper regard for his safety,” the source added.

Police Chief William Bratton is waiting for the final toxicology reports.

“Based on those, we will have an idea what we are dealing with. Are we dealing with a homicide or are we dealing with accidental overdose?” he said.

At least four doctors are at the core of the investigation. One, personal physician Dr. Conrad Murray, was with Jacko when he collapsed. (ANI)