Factbox: Key evidence, testimony in Jackson doctor trial

Michael Jackson's former physician, Dr. Conrad Murray, is on trial for involuntary manslaughter in the Thriller singer's 2009 death. Closing arguments take place on Thursday and a Los Angeles jury will deliberate shortly afterward before deciding Murray's guilt or innocence.

Prosecutors claim Murray was negligent in giving the singer the anesthetic propofol as a sleep aid after rehearsals for a series of concerts. The defense claims Jackson may have given himself a fatal dose of the powerful drug.

Here are key points of evidence and arguments presented by prosecutors and defense attorneys in the trial:

PROSECUTION:

* The involuntary manslaughter charge against Murray is based on gross negligence and a related assessment by doctors that Murray repeatedly violated the standard of care, which is what patients can expect as the base of safe healthcare.

* Murray admitted in an interview with police that he administered a relatively small dose of 25 milligrams of propofol as a sleep aid to Jackson in the singer's bedroom.

* Propofol expert Dr. Steven Shafer theorized Murray placed Jackson on an intravenous drip of propofol that resulted in the singer receiving as much as 40 times more of the drug than the single, 25-milligram injection Murray said he gave.

* A half-dozen doctors testified that propofol should be given in a hospital or surgery center, not at a home, as the drug can stop a patient from breathing and proper monitoring and medical equipment need to be on hand for an emergency.

* Several doctors faulted Murray for using propofol almost daily, contrary to its typical use. We are in pharmacological Never-Never Land here, something that's only been done to Michael Jackson, said Dr. Steven Shafer.

* Jurors saw an instructional video that showed the correct method of administering propofol and highlighted crucial pieces of equipment, such as an infusion pump and electrocardiograph machine, that were missing from Jackson's bedroom.

* Doctors said Murray responded amateurishly after discovering Jackson stopped breathing. Records indicate over 20 minutes elapsed before paramedics were called. It's basic knowledge in America, you don't have to be a healthcare professional, that when someone is down you need to call 911 for help, testified Dr. Alon Steinberg.

DEFENSE:

* Propofol expert Dr. Paul White testified that Jackson likely injected himself with an extra, fatal dose of 25 milligrams of propofol when Murray was absent. He based his finding on levels of the anesthetic found in Jackson's urine at autopsy. Under that scenario, Jackson would have used a syringe with propofol left behind by Murray, White said.

* White said that, based on blood levels of the sedative lorazepam found at Jackson's autopsy, the singer might have swallowed eight tablets of the drug hours before his death. Murray has admitted giving Jackson two shots of two milligrams of lorazepam.

* The defense team's assertion of a hypothetical, final shot of propofol Jackson may have given himself was amplified by the effect of sedatives already in his system, White said.

* Addiction specialist Dr. Robert Waldman reviewed medical records of Jackson's visits to Beverly Hills dermatologist Dr. Arnold Klein in the months before the singer's death. Waldman said Jackson appeared to have grown physically dependent on the painkiller Demerol that he received repeatedly from Klein.

* One symptom of Demerol withdrawal is insomnia, Waldman said. Murray's attorneys argued the Demerol shots Jackson received hampered Murray's efforts to get the singer to sleep.