In October, a jury rejected Katherine Jackson's lawsuit claiming concert promoter AEG Live negligently hired Conrad Murray, the doctor who was convicted of involuntary manslaughter for giving her son an overdose of the anesthetic propofol in 2009.
The jury found that while AEG Live hired Murray, the doctor was competent to do the job he was hired to do. Jurors agreed with AEG Live that the concert promoter expected Murray to be a basic doctor, providing basic medical care for the pop star -- not secretly providing Jackson with propofol as an insomnia treatment.
Katherine Jackson's lawyers now say that the verdict form didn't allow jurors to consider all of the evidence in the negligence case. Lawyers for AEG Live countered that there was no basis for a new trial.
Superior Court Judge Yvette Palazuelos did not immediately finalize the ruling after hearing more than two hours of arguments from both sides on Friday.
AEG attorney Marvin Putnam said the motion for a new trial is "desperate" and "not that surprising."
About the question on the verdict form, AEG argues it was the Jackson attorneys who repeatedly requested the wording that they now say is faulty.
"What the jurors came back and said rather definitively is that they didn't prove their case. And they didn't prove their case because what they alleged to have occurred never occurred," said Putnam.
But the Jackson attorneys say some jurors were confused. They have affidavits from four of them who said they wanted to deliberate further on AEG's role.
"They were supervising Conrad Murray. The question was, were they doing so reasonably? That is what we're saying the jury never got a chance to decide," said Jackson attorney Kevin Boyle.
If Palazuelos stands by her ruling, the Jackson attorneys could file an appeal with a higher state court.
The Associated Press contributed to this report.