Defense attorneys want the second sanity exam of the Aurora movie theater gunman tossed out, the latest sign that a contentious debate over James Holmes’ mental health will dominate the trial.

In a motion filed Thursday, defense attorneys ask that the exam be stricken from evidence at trial or that the judge “limit the opinions and testimony of the second sanity examiner.” The motion was filed under seal, but its title was disclosed in a judge’s order.

In two other motions filed Thursday, defense attorneys ask that video recordings of the sanity exam not be allowed into evidence and that certain statements Holmes made to the examiner, psychiatrist William Reid, also been excluded. In the latter motion, defense attorneys write that “Dr. Reid’s examination is fundamentally unreliable as a whole.”

The motion provides the latest signal that Holmes’ trial for the Century Aurora 16 attack will become a “battle of the experts” over Holmes’ sanity. The second exam, an unusual step in insanity cases, was ordered after prosecutors challenged the credibility of the first exam. The results of neither exam have been released. Both sides also have hired at least two experts each to opine about Holmes’ sanity.

Holmes has pleaded not guilty by reason of insanity to charges that he murdered 12 people and tried to kill 70 more in the attack. Jury selection for the trial is now set to begin in January, after the judge ordered a six-week delay earlier this week.

The delay, though, means roughly 70,000 more potential jurors will be eligible to be summoned in the case. When 6,000 jury summonses are sent out either later this year or early next year for the long-awaited trial, people on the jury rolls in Arapahoe County will have a 1-in-75 chance of being called.

Jon Sarche, a spokesman for the Colorado Judicial Branch, said a person can be called for jury duty only once per calendar year. About 1,500 people are called for jury duty per week in Arapahoe County, where the theater shooting trial will take place. That means about 70,000 people who had already been called this year would have been excluded from receiving summonses for the trial had jury selection begun at the end of this year. With jury selection in January, court administrators will have almost the entire 450,000-person jury pool in Arapahoe County eligible to be summoned.