Jackson ‘used anaesthetic drip’ before his death

Police and drug enforcement officers raided the Las Vegas home of Michael Jackson's personal doctor, Conrad Murray, yesterday as reports emerged that by the time of his death the pop star was reliant on the powerful anaesthetic propofol to enable him to sleep - so much so, that it was administered by intravenous drip.

An official involved in the investigation into Jackson's death told the Associated Press that the propofol drip would literally render Jackson unconscious. When it was time for him to wake up, the drip would be stopped.

Confirmation of Jackson's use of propofol is expected when the LA coroner receives the results of toxicology tests on his body, due this week.

The raid on Murray's house follows a similar search of his office in Houston, Texas a week ago (pictured). The doctor has not been declared a suspect, but the police action is part of an investigation into possible manslaughter.

Murray, a 51-year-old cardiologist, was employed in May by AEG Live, promoters of the doomed London concerts, to act as Jackson's personal physician. He moved into Jackson's rented house in Holmby Hills and was with the singer when he collapsed on June 25. He tried in vain to resuscitate him.

The entertainment news site TMZ.com reports today that Murray is one of more than a dozen doctors being investigated by police for fraudulent prescription practices in the light of Jackson's death. The pop star is said to have used more than 20 aliases to get drugs with doctors' help, and the investigation could blow wide open the practice of doctors helping celebrity patients fuel their drug addiction.

TMZ.com has also reported that Murray himself has confirmed administering propofol to Jackson. However, Murray's lawyer, Edward Chernoff, has denied that Murray gave Jackson anything that could have killed him and refused to respond to "rumours, innuendo or unnamed sources".

According to the Guardian, propofol is an increasingly popular sedative among hospital anaesthetists because it works quickly and effectively. But anyone on a propofol drip has to be monitored closely because it is very powerful and the dosage has to be spot on: a dosage just one tenth of a cc too high can cause heart failure.