Michael Jackson's personal doctor has been identified as the target of a manslaughter investigation into the singer's death, US court papers say.

Dr Conrad Murray's medical clinic in Houston, Texas, and another site rented by him were searched on Wednesday.

Police have said previously that Dr Murray is not a suspect but the search warrant allowed the authorities to seek evidence of manslaughter.

The doctor was at Jackson's mansion and tried to revive him before he died.

Dr Murray has already been interviewed twice by police, who had asked for medical records in addition to those already provided.

He has not been arrested or formally charged.

Unwelcome attention

According to the warrant, approved by a Houston judge and filed in Harris County District Court, authorities were looking for "items constituting evidence of the offence of manslaughter that tend to show that Dr Conrad Murray committed the said criminal offence".

Items seized during the searches included 27 tablets of the weight loss drug phentermine, a tablet of the muscle relaxant clonazepam, two hard drives, notices from the Internal Revenue Service and a controlled substance registration.

Speaking a few days after Jackson's death, Dr Murray's lawyer, Edward Chernoff, denied his client administered painkilling drugs that could have contributed to the singer's death.

But he said that, because of his closeness to Jackson at his death, the doctor had received unwelcome attention from people angry at the singer's demise.

Mr Chernoff was present at Wednesday's searches.

"I do not know what they are looking for and I can't possibly tell you how anything they took in any way connects with the death of Michael Jackson," he was quoted by the Los Angeles Times as saying.

The BBC's Peter Bowes in Los Angeles, where Jackson died, says it is now up to public prosecutors to sift through the considerable amount of evidence and decide whether to charge Dr Murray.

An official determination of what killed Jackson will not be made until after a toxicology report, which is expected to be completed next week.