Los Angeles (CNN) -- Michael Jackson "clearly" suffered from insomnia that could have been caused by Demerol, a narcotic he was getting frequently from a doctor other than Dr. Conrad Murray, according to a sleep expert testifying Thursday in Murray's involuntary manslaughter trial. Murray's defense team contends Dr. Arnold Klein injected Jackson with 6,500 milligrams of Demerol during visits to his Beverly Hills, California, dermatology clinic in the last three months of his life, and that Murray did not know about it. Jackson desperately sought sleep the day he died, worried that without rest he could not rehearse that night, which could force the cancellation of his "This Is It" comeback concerts, according to Murray's interview with police.
@highlight
NEW: Dr. Klein injected 6,500 milligrams of Demerol into Jackson, the defense says
@highlight
NEW: Jackson's insomnia could have been caused by Demerol, a sleep expert says
@highlight
NEW: Trial could end early, judge says
@highlight
Anesthesiologist Dr. Steven Shafer may be the prosecution's last witness
Arnold Klein
Klein
@placeholder was never charged or disciplined for his treatment of Jackson, but Murray's lawyers contend that treatment addicted Jackson to Demerol and caused the insomnia that Murray was treating when Jackson died.
Michael Jackson
Jackson
Jackson
Jackson
Jackson
Klein was never charged or disciplined for his treatment of @placeholder, but Murray's lawyers contend that treatment addicted Jackson to Demerol and caused the insomnia that Murray was treating when Jackson died.
Demerol
Demerol
Demerol
Demerol
Klein was never charged or disciplined for his treatment of Jackson, but Murray's lawyers contend that treatment addicted Jackson to @placeholder and caused the insomnia that Murray was treating when Jackson died.
Michael Jackson
Jackson
Jackson
Jackson
Jackson
Murray claimed the day Jackson died he was trying to wean @placeholder from using the surgical anesthetic propofol to induce sleep, a treatment he gave him almost every night the previous two months.
Michael Jackson
Jackson
Jackson
Jackson
Jackson
Murray told detectives that during the last morning he gave @placeholder a series of three sedatives -- Valium, lorazepam and midazolam -- over a 10-hour period before finally giving in to Jackson's plea to again use propofol.
Michael Jackson
Jackson
Jackson
Jackson
Jackson
Murray told detectives that during the last morning he gave Jackson a series of three sedatives -- Valium, lorazepam and midazolam -- over a 10-hour period before finally giving in to @placeholder's plea to again use propofol.
Conrad Murray
Murray
Murray
Murray
Murray
"I've got to sleep, Dr. @placeholder," Murray said Jackson pleaded to him.
Conrad Murray
Murray
Murray
Murray
Murray
He is expected to be the next and last witness for the direct presentation of the prosecution's case against @placeholder.
Conrad Murray
Murray
Murray
Murray
Murray
The prosecution has been unable to produce the tubing that would be a critical piece of an IV system, although they did show jurors an opened saline bag into which they contend @placeholder placed an opened propofol bottle.