Los Angeles (CNN) -- Testimony in the trial of Michael Jackson's doctor has been put on hold beyond Monday, and possibly longer, because the father of the prosecution's last witness died.
"Resumption of the trial will be announced when further information is available," an email from the court said Sunday.
Dr. Conrad Murray's involuntary manslaughter trial is expected to go to the jury early next week despite the delay, several days sooner than estimated when it began three weeks ago.
Dr. Steven Shafer, an anesthesiology expert, is crucial to the state's effort to prove Jackson's death was caused by Murray's gross negligence in using the surgical anesthetic propofol to help the pop icon sleep.
The Los Angeles County coroner ruled that Jackson's June 25, 2009, death was from "acute propofol intoxication" in combination with several sedatives, including lorazepam.
Shafer began testifying Thursday morning before the judge recessed for the weekend so he could travel to a medical convention. He never made it there because of the death in his family, Deputy District Attorney David Walgren said Friday.
Shafer, who is expected to give a detailed scientific explanation of how propofol is metabolized in the human body, will be on the witness stand for at least a day once he returns from his father's funeral, according to what Walgren said Friday.
Shafer's testimony is expected to echo the opinions of a sleep expert and a cardiologist who testified that Murray's treatment of Jackson was so grossly negligent that it was criminal.
The defense presentation would follow, lasting until Friday or the following Monday, according to defense lawyer Nareg Gourjian.
Along with two or three medical experts and a police officer not called by the prosecution, the defense has lined up several patients of Dr. Murray to testify about how he's helped them, Gourjian said.
There is no indication Murray will take the stand to testify in his defense, which would subject him to intense cross-examination by Walgren. The jury already heard the recording of his interview with detectives two days after Jackson's death.
Murray's lawyers contend that Jackson used a syringe to inject the fatal overdose through a catheter on his left leg while Murray was away from his bedside. They dropped the theory pushed earlier that Jackson may have orally ingested the propofol that the coroner says killed him.
Murray's defense also contends that Jackson swallowed eight tablets of lorazepam, a sedative, in a desperate search for sleep the day he died.
Murray should be found guilty even if jurors accept the theory that Jackson self-administered the fatal dose because the doctor was reckless in leaving propofol and lorazepam near his patient when he was not around, Dr. Alon Steinberg, a cardiologist testifying for the prosecution, said last week.
"It's like leaving a baby that's sleeping on your kitchen countertop," Steinberg said. "There's a very small chance the baby could fall over, or wake up and grab a knife or something."
On Thursday, UCLA sleep expert Dr. Nader Kamangar testified that the combination of drugs Murray gave Jackson "was the perfect storm" that killed him.
"Mr. Jackson was receiving very inappropriate therapy, in the home setting, receiving very potent sedatives, including propofol, lorazepam and midazolam, without monitoring by Murray, and ultimately this cocktail was a recipe for disaster," Kamangar said.
But Kamangar, testifying for the prosecution, said Jackson "clearly" suffered from insomnia that could have been caused by Demerol, a narcotic he was getting frequently from a doctor other than Murray.
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.
If convicted of involuntary manslaughter, the maximum sentence Murray could face is four years in prison and the loss of his medical license.