Michael Jackson's doctor has been officially named as the target of a manslaughter investigation into the singer's death.

According to reports, Dr. Conrad Murray - who was with the 50-year-old pop icon when he died of a suspected cardiac arrest last month, and tried to revive him with CPR (cardiopulmonary resuscitation) - has been named in court papers filed in Houston yesterday (23.07.09).

It is the first time records have shown Murray is being formally investigated by police, although he has previously been questioned about the events leading up to Jackson's death.

On Wednesday (22.07.09), police and officers from the Drug Enforcement Agency (DEA) raided Murray's Houston offices looking for "items constituting evidence of the offense of manslaughter".

According to reports items seized from the storage unit included "two computer hard drives, a Medical Board certificate, letters to a former employee, a list of contacts and papers pertaining to his practice. Among those is a 'suspension notice from Doctor's Hospital' and 'papers regarding incomplete chart at Doctor's Hospital'."

An administrative assistant at Houston's Doctor's Hospital confirmed Murray is suspended at the moment, but insisted it was over a routine matter that "probably had something to do with a chart that needs to be signed".

Other items taken were two drug vials, 27 phentermine - which suppresses appetite - tablets, one pill of muscle relaxant clonazepam, a rolodex, a computer and emails.

The emails are thought to be of high importance in any investigation against Murray.

Loyola Law School professor Laurie Levenson said: "The emails are key. What did Dr. Murray say to other people after Michael Jackson died? And was it he that ordered the drugs. The paperwork always wins these cases and the emails are critical. By this time next week, we'll have a better idea."

It has been claimed the warrant means police are already aware of the findings of the preliminary autopsy report, including which drugs Jackson was taking at the time of his death.

According to reports, police are focusing their investigation on the 50-year-old singer's use of the anaesthetic Propofol, which is used to put patients to sleep before surgery.

Reports suggest the autopsy results will be released next week, and homicide will be stated as the cause of death.

Gossip website TMZ reports: "We're told the coroner himself will make the call mid-week, after he gets the final toxicology report from an outside consultant. But based on the draft report as well as what has become 'clear evidence' causes other than homicide - natural, accidental, accidental overdose and suicide - have been ruled out.

"We're told both the coroner and police have significant evidence that Propofol caused Jackson's heart to stop."