LOS ANGELES (AP) -- The battle of scientific experts in the trial of Michael Jackson's doctor took a new turn late Thursday as defense lawyers made an 11th hour disclosure that their scientific expert has devised a new computer simulation shedding light on what killed the pop superstar.
Prosecutors told the judge they were surprised by the new development and need time to study the software program used by Dr. Paul White, a top expert on the anesthetic propofol. The judge agreed.
He said White could conclude his defense testimony Friday but he would give the prosecution the weekend to analyze the computer data before the star witness of Dr. Conrad Murray's defense is cross-examined.
"This is extraordinarily complicated material," said Superior Court Judge Michael Pastor.
The developments were gleaned at the end of the court day from a transcript of a lengthy private conference with lawyers in the judge's chambers.
The new twist means another delay in the trial's conclusion, the judge said, and he worried aloud, "I just don't know if we are going to start losing jurors."
"This jury is extraordinarily dedicated to the case," he said. "But they have lives and commitments."
Jurors were told at the outset that they would be finished with the trial Friday, Pastor said. Now, he said, he's not sure when the trial will conclude.
The defense, meanwhile, sought to shift blame to another doctor and a drug different from the anesthetic that killed Jackson. Murray's lawyers called an expert to testify that the star was addicted to a Demerol in the months before his death.
They suggested the singer's withdrawal from the painkiller triggered the insomnia that Murray was trying to resolve when he gave Jackson propofol.
Murray's attorneys claim the ultimate blame lies with Jackson himself, but they also sought to implicate his dermatologist in the drug-laced path to his June 2009 death.
They called White to the stand late in the day to cast doubt on a colleague's earlier testimony that Murray was responsible for Jackson's death.
Court recessed before White gave his central opinion. He did say he was "perplexed" after reading documents in the case about whether Murray administered the propofol dose that killed Jackson.
White noted that Murray described to police a very low dose of the drug. If that was true, White said, "I would not have expected Michael Jackson to have died."
White said if Murray did in fact put Jackson on an IV drip of propofol and leave him unattended, he could not justify it. White did not immediately offer an alternate theory of what happened.
Authorities contend Murray delivered the lethal dose and botched resuscitation efforts. Murray has pleaded not guilty to involuntary manslaughter in Jackson's death.
There was no mention of propofol during the testimony of Dr. Robert Waldman, an addiction expert who said he studied the records of Dr. Arnold Klein, Jackson's longtime dermatologist, in concluding the star was dependent on Demerol. Records showed Klein used Demerol on Jackson repeatedly for procedures to enhance his appearance.
No Demerol was discovered in the singer's system when he died, but propofol was found throughout his body.
Waldman relied on Klein's records from March 2009 until days before Jackson died. Waldman said he was not shown earlier records and didn't review a police interview of Murray about his treatment of the star.
Under questioning by Murray's lead lawyer, Ed Chernoff, Waldman said, "I believe there is evidence that he (Jackson) was dependent on Demerol, possibly."
Klein has emerged as the missing link in the involuntary manslaughter trial, with the defense raising his name at every turn and the judge ruling he may not be called as a witness because his care of Jackson is not at issue. He has not been charged with any wrongdoing.
But Klein's handwritten notes on his visits with Jackson were introduced through Waldman, who said Klein was giving Jackson unusually high doses of Demerol for four months - from March through June 2009 - with the last shots coming three days before the singer's death.
Over three days in April, the records showed Jackson received 775 milligrams of Demerol along with small doses of the sedative Versed. Waldman's testimony showed Klein, who also was Jackson's longtime friend, was giving the singer huge doses of the powerful drug at the same time Murray was giving Jackson the anesthetic propofol to sleep.
"This is a large dose for an opioid for a dermatology procedure in an office," Waldman said.
He told jurors the escalating doses showed Jackson had developed a tolerance to the drug and was probably addicted. He said a withdrawal symptom from the drug is insomnia.
On cross-examination, prosecutor David Walgren tangled with the expert, who was hostile to most of his questions. He elicited from Waldman that the law requires physicians to keep accurate and detailed records, which Murray did not. The doctor also said all drugs should be kept in a locked cabinet or safe where they could not be stolen or diverted by anyone.
Waldman said every doctor also must document when the drugs are stored and when they are used. Murray told police he kept no records on his treatment of Jackson.
Waldman, who has treated celebrities and sports stars at expensive rehab clinics, told jurors treatment can work if the addict is willing to admit a problem.
Several prosecution experts have said the propofol self-administration defense was improbable, and a key expert said he ruled it out completely, arguing the more likely scenario was that Murray gave Jackson a much higher dose than he has acknowledged.
Jackson had complained of insomnia as he prepared for a series of comeback concerts and was receiving the anesthetic and sedatives from Murray to help him sleep.
Murray's police interview indicates he didn't know Jackson was being treated by Klein and was receiving other drugs.
In response to questions from a prosecutor, Waldman said some of the symptoms of Demerol withdrawal were the same as those seen in patients withdrawing from the sedatives lorazepam and diazepam. Murray had been giving Jackson both drugs.
White is expected to be the final defense witness.
White and Waldman do not necessarily have to convince jurors that Jackson gave himself the fatal dose, but merely provide them with enough reasonable doubt about the prosecution's case against Murray.