MICHAEL Jackson had lethal levels of powerful painkiller Demerol and heroin substitute methadone in his body when he died, The Sun can reveal.
Tests show the tragic star had taken a cocktail of drugs strong enough to have killed any normal person instantly. 
But he had been on vast quantities so long his body became tolerant to huge doses - until his fatal collapse on Thursday of last week.
The shock findings are in preliminary toxicology reports submitted to the Los Angeles county coroner’s office.
The contents were revealed as sources predicted Jacko’s death could result in manslaughter or even MURDER charges.
A case insider told The Sun: “Michael Jackson was a walking drug store when he died — he never stood a chance.”
As well as lethal levels of DEMEROL and METHADONE, blood tests found high levels of antianxiety drug XANAX.
Also present were lower levels of PROPOFOL — an anaesthetic for hospital use only, but which Jackson used as a sleeping draft.
A significant amount of narcotic DILAUDID, normally used to numb post-surgery pain, was discovered.
In addition there were “therapeutic” levels of FENTANYL, another post-op painkiller 100 times more potent than morphine, plus prescription painkiller VICODIN, anti-anxiety pills VALIUM and the sleeping drug AMBIEN.
The insider said: “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.
Pressure
“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.”
Police Chief William Bratton said he was waiting for the final toxicology reports, currently weeks away.
He added: “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?”
The early findings support The Sun’s exclusive revelation that 50-year-old King of Pop was given an injection of Demerol about 40 minutes before his heart stopped.
Jackson’s dermatologist Dr Arnold Klein — the close pal rumoured to be the father of two of the star’s three children — has already admitted occasionally giving Jackson Demerol after surgery.
But he insisted he had warned him about Propofol, also known as Diprivan.
Klein said: “I knew at one point he was using Diprivan was on tour in Germany. I told him he was absolutely insane. I said, ‘You have to quit it. This drug, you can’t repeatedly take’.”
Jackson last toured Germany in 1997 — indicating he may have been taking the potentially lethal medication for at least 12 years.
At least four doctors are at the core of the investigation. One, personal physician Dr Conrad Murray, was with Jacko when he collapsed.
Yesterday a letter from a Dr Alex Farshchian and dated July 21, 2002, emerged suggesting Jackson trade his dependence on Demerol for injectable painkiller Buprenex.
Said to have been found at Jackson’s rented house and published on a US website, it said: “Buprenex is the potent narcotic I told you about last week. It is just like the D but better.” The letter suggests a five to seven-day program “that offers you the solution”.
The doctor adds: “I have everything ready. This is it.”
Eerily, seven years later This Is It would be the title Jackson chose for his comeback shows.
A scribbled note found near his drug stash, possibly written by Jackson, said: “Buprenex does the same as Demerol, the only difference is you can’t become an addict on Buprenex.”
Another letter — headed Outpatient Detoxification Sheet — names methadone as the most common way to treat drug dependency.
Meanwhile documents and snaps from the Santa Barbara County Sheriff’s department also emerged showing the depths of Jackson’s drug habit were uncovered in 2003.
Officers raided his Neverland home while probing child abuse claims — and found powerful narcotics, syringes, vials and IV bags.
Jackson had been so desperate to score prescription drugs that he even used his best friend’s identity.
Among the police snaps is one showing a bottle of anti-anxiety drug Alprazolum, also known as Xanax, in the name Frank Tyson — prescribed by Dr Klein.
Tyson’s real name is Frank Cascio. He is a pal’s son who Jackson befriended as a toddler and put on his payroll when he turned 18.
Frank hung out with him at Elizabeth Taylor’s Swiss chalet in Gstaad in September 1993. And Jackson often sought sanctuary in Frank’s New Jersey home — once spending three months there.
It is thought Frank, now 30, had no idea Jackson was using his name like this — though the star frequently begged aides to get him prescription drugs to top up his own legal supply.
In 2004 bodyguard Chris Carter told investigators he used several names to get prescriptions, including those of ranch manager Jesus Salas and employee Joe Marcus.
Carter also claimed Jacko was once so “spaced out” he fell flat on his face in a hotel — but still continued the drug binge which five years later would lead to his death.
The progress of the drug addictions is to be mapped by a battery of tests — to Jackson’s BRAIN.
It was removed before Tuesday’s memorial service and slices will show when he first suffered drug reactions.
Renowned pathologist Dr Michael Baden said: “Everything from whether he was beaten as a child to any small tumours, or previous overdoses that he may have suffered, will show up.
“The brain results will determine if he was given improper medication, and how authentic statements provided by his physicians were.”
THE human body can build up a startling tolerance to morphine-based and tranquilliser drugs, writes Health and Science Editor Emma Morton. The phenomenon, tachyphylaxis, means larger and larger doses are needed to have an effect. This puts massive pressure on the heart, triggering heart failure.
