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Sleep expert testifies Thursday in the Conrad Murray trial

Dr. Conrad Murray, left, listens while seated beside defense attorney Nareg Gourjian during his involuntary manslaughter trial, Wednesday, Oct. 12, 2011, in downtown Los Angeles. Murray has pleaded not guilty and faces four years in prison and the loss of his medical license if convicted of involuntary manslaughter in Michael Jackson's death.
Pool,AP Photo/Robyn Beck
Dr. Conrad Murray
Pool,AP Photo/Robyn Beck

(CBS/AP) LOS ANGELES - Testimony resumed Thursday in the involuntary manslaughter trial of Michael Jackson's physician with Dr. Nader Kamanger, a UCLA sleep expert, being cross-examined by Defense Attorney J. Michael Flanagan about Jackson's insomnia.

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The defense case shifted Wednesday when an attorney for Dr. Conrad Murray revealed he was abandoning the theory that Jackson swallowed the fatal dose of the anesthetic propofol.

The Houston-based cardiologist has pleaded not guilty, and his attorneys have repeatedly told jurors they will show Jackson self-administered either the anesthetic or the sedative lorazepam without Murray's knowledge. They had invested months before the trial on the theory that Jackson somehow drank propofol and caused his own death.

Flanagan stunned a judge and prosecutors before testimony resumed Wednesday by saying the results of a study he commissioned confirmed that if Jackson swallowed the anesthetic, its effects would be "trivial." He said the issue wouldn't be raised with jurors.

Murray's attorneys may still argue that Jackson gave himself the fatal dose of the drugs, but a pair of experts told jurors that even if that happened, it didn't change that Murray went far astray from medical norms.

The experts, a cardiologist and a Kamanger who both practice emergency medicine, said Murray should have never been giving Jackson propofol as a sleep aid.

Complete coverage of the Conrad Murray - Michael Jackson case on CBS News