Prosecutors concluded their case Monday against the doctor charged with Michael Jackson's death after questioning 33 witnesses, including an expert who said the physician committed numerous violations of medical practices that could have led to the singer's serious injury or death.
Defense attorneys quickly called their first witness -- Dona Norris, a records custodian for the Beverly Hills Police Department who discussed the 911 call received on the day Jackson died.
She was one of 15 defense witnesses expected witnesses over the next few days.
The final prosecution witness against defendant Dr. Conrad Murray was Dr. Steven Shafer, an expert on the anesthetic propofol that authorities say killed Jackson.
Shafer told jurors that it's difficult to know the precise effects of the drug on the singer because he had been given so much of it in the months before he died.
Shafer made the statement while being cross-examined by lead defense attorney Ed Chernoff, who noted the risk that Jackson would stop breathing should have been low after the first few minutes the drug was administered on the day he died.
Chernoff based that conclusion on models and research done by Shafer.
"In Mr. Jackson's case, it's harder to have that certainty," Shafer replied. "There's very little, almost no precedent for this level of propofol exposure."
Shafer, a Columbia University researcher and professor, said Jackson had been receiving propofol almost every night for more than two months, according to a police statement by Murray. The Houston-based cardiologist has pleaded not guilty to involuntary manslaughter.
Shafer previously testified that he thinks a propofol overdose killed Jackson. But he said Murray kept no records about how much of the drug he gave the singer.
Shafer has said the only possible explanation for Jackson's death based on the evidence was that Murray put the singer on an IV drip of propofol then left the room after the singer appeared to be asleep.
Murray's attorneys will try to counter four weeks of damaging testimony from 33 prosecution witnesses who have cast Murray as an inept, distracted and opportunistic doctor who repeatedly broke legal, ethical and professional guidelines.
Murray's attorneys have not publicly revealed whether they will call him to testify.
Jurors have heard from the doctor through a more than two-hour interview with police, and it seems unlikely his attorneys would subject their client to what would be blistering questioning from prosecutors.
Shafer has not retreated from his position that Murray is solely responsible for Jackson's death and that the cardiologist committed 17 egregious violations of medical practices that each could have either led to Jackson's serious injury or death.
Out of sight of the jury, the defense's theory has shifted in recent months from arguing that Jackson swallowed propofol and gave himself the fatal dose and more recently that the singer had swallowed several pills of the sedative lorazepam, which led to his death.
They might also argue that Jackson somehow gave himself a shot of propofol after Murray left the room, killing him quickly.