In 2020, Peterson received a pair of favorable rulings in the California Supreme Court.
The first ruling came in Peterson's appeal of his conviction and sentence.
The high court found that the trial judge excluded jurors from the jury pool when they said that they were personally opposed to the death penalty, without first determining whether the prospective jurors would be able to set aside their personal views about capital punishment and follow the law as the trial judge instructed.
The court therefore struck the death penalty sentence and sent the case back to the trial court to hold a new penalty trial.