Pop star Michael Jackson had lethal¹ levels of the powerful anaesthetic propofol in his body when he died, coroner's office documents show.

验尸官办公室文件显示，巨星Michael Jackson遗体内含有可以达到致死水平的强烈麻醉剂丙泊酚。

The findings were contained in a previously² sealed search warrant which has been made public in Houston.

The singer died on 25 June at the age of 50 after suffering a cardiac arrest（心搏停止） at his home in Los Angeles.

Jackson's doctor Conrad Murray has been interviewed twice by police but has not been named as an official suspect.

Details of the LA county coroners' findings were revealed when a search warrant affidavit³（宣誓书） was made public in Houston, Texas, where Dr Murray has offices.

Dr Murray's offices were raided last month as part of the police investigation⁴ into the singer's death.

Investigators⁵ are trying to establish if there is a case for manslaughter, based on medical negligence⁶（疏忽，粗心大意）, the BBC's Rajesh Mirchandani in Los Angeles says.

The coroner's office has not published its findings regarding the singer's death.

It has also declined to comment on a report from the Associated Press news agency that an unnamed police source says the coroner has ruled Jackson's death was a homicide.

Addiction⁷ fears

According to the affidavit, the LA chief coroner "had reviewed the preliminary toxicology（毒物学） results and his preliminary assessment⁸ of Jackson's cause of death was due to lethal levels of propofol".

The documents go on to say that Dr Murray told police he had been giving Jackson propofol as part of his treatment for insomnia⁹（失眠）.

But, he said he had been concerned Jackson was becoming addicted¹⁰ to the drug and had been trying to wean（戒掉） him off, using alternative drugs.

But, on the morning of the singer's death, Dr Murray is reported to have relented（变宽厚，变温和） and given Jackson a lower dosage（药量） of propofol after a number of other drugs had not worked.

He left the star alone to make some telephone calls and when he returned Jackson was not breathing, the LA Times reports.

Dr Murray is known to have performed CPR on his patient while the paramedics（护理人员） were called, but Jackson was declared dead when he arrived at hospital.

Bottles of propofol found in Jackson's house show it had been prescribed（规定的） by several doctors, not just Conrad Murray, but he remains¹¹ at the centre of the inquiry¹², our correspondent adds.

Earlier this month, Dr Murray - who was employed as Michael Jackson's personal physician for a series of concerts in London scheduled for July - posted a video message of YouTube to thank his supporters.

"I told the truth and I have faith the truth will prevail（获胜，流行）," he said in the short one-minute clip.