12 October 2011 Last updated at 20:53

Conrad Murray drops claim Jackson swallowed propofol

Lawyers for Dr Conrad Murray have stepped back from claims that Michael Jackson swallowed a fatal dose of propofol when he was out of sight.

The claim had been a key argument in Dr Murray's defence at the trial over the superstar's death. They may still argue he injected the dose himself.

The change came a day after the doctor who performed Jackson's autopsy said he could not have self-administered it.

Dr Murray has pleaded not guilty to involuntary manslaughter.

If convicted Dr Murray could face up to four years in prison and the loss of his medical licence.

Both the prosecution and Superior Court Judge Michael Pastor appeared surprised by Wednesday's disclosure, reports said.

'Trivial' effect

J Michael Flanagan, one of Dr Murray's lawyers, said he had commissioned a study about the effects of swallowed propofol.

Mr Flanagan said the effects from swallowing propofol, a powerful anaesthetic that Dr Murray injected to relieve Jackson's insomnia, would be "trivial".

"We are not going to assert at any time during this trial that Michael Jackson orally administered propofol," Mr Flanagan said.

The disclosure was made in court but not in front of jurors, the Associated Press reported.

Lead defence lawyer Ed Chernoff said during opening statements on 27 September that his team would try to show that Jackson gave himself the fatal dose of propofol.

On Tuesday, Dr Christopher Rogers said it was more likely Jackson's Dr Murray mistakenly gave Jackson too much of the drug in an effort to help him sleep.

"The circumstances, from my point of view, do not support self-administration of propofol," the chief of forensic medicine at the Los Angeles County Coroner's Office said.