CRIME

Theater shooting case draws huge pool of possible jurors to decide if suspect was insane

  • FILE -- This Thursday, Jan. 15, 2015 file photo shows a view of the jury box, right, inside Courtroom 201, where jury selection in the trial of Aurora movie theater shootings defendant James Holmes is to begin on Jan. 20 at the Arapahoe County District Court in Centennial, Colo. The trial begins with 9,000 possible jurors and a rare opportunity to see a mass shooter stand trial. (AP Photo/Brennan Linsley, Pool, File)

    FILE -- This Thursday, Jan. 15, 2015 file photo shows a view of the jury box, right, inside Courtroom 201, where jury selection in the trial of Aurora movie theater shootings defendant James Holmes is to begin on Jan. 20 at the Arapahoe County District Court in Centennial, Colo. The trial begins with 9,000 possible jurors and a rare opportunity to see a mass shooter stand trial. (AP Photo/Brennan Linsley, Pool, File)  (The Associated Press)

  • FILE - In this Dec. 8, 2014, file photo,  Arapahoe County, Colo. District Attorney George Brauchler, left, walks with an unidentified man out of courtroom after a pre-trial readiness hearing in Centennial, Colo., in the murder trial of James Holmes, who is charged with killing 12 moviegoers and wounding 70 more in a shooting spree in a crowded theatre in Aurora, Colo., in July 2012. The trial is set to start on Tuesday, Jan. 20, 2015. (AP Photo/David Zalubowski, File)

    FILE - In this Dec. 8, 2014, file photo, Arapahoe County, Colo. District Attorney George Brauchler, left, walks with an unidentified man out of courtroom after a pre-trial readiness hearing in Centennial, Colo., in the murder trial of James Holmes, who is charged with killing 12 moviegoers and wounding 70 more in a shooting spree in a crowded theatre in Aurora, Colo., in July 2012. The trial is set to start on Tuesday, Jan. 20, 2015. (AP Photo/David Zalubowski, File)  (The Associated Press)

  • FILE - In this July 24, 2012 file photo, members of the the prosecution team from the Arapahoe County District Attorney's office leave the Century 16 theater after spending more than an hour there in Aurora, Colo. Jury selection begins Tuesday, Jan. 20, 2015, in the trial of accused gunman James Holmes in the shootings at the Denver-area movie theater showing "The Dark Knight Rises" that left 12 dead and 70 wounded. Prosecutors are seeking the death penalty. Holmes pleaded not guilty by reason of insanity. His attorneys have acknowledged he was the gunman but say he is mentally ill and was gripped by a psychotic episode when he opened fire in the theater. (AP Photo/Ed Andrieski, File)

    FILE - In this July 24, 2012 file photo, members of the the prosecution team from the Arapahoe County District Attorney's office leave the Century 16 theater after spending more than an hour there in Aurora, Colo. Jury selection begins Tuesday, Jan. 20, 2015, in the trial of accused gunman James Holmes in the shootings at the Denver-area movie theater showing "The Dark Knight Rises" that left 12 dead and 70 wounded. Prosecutors are seeking the death penalty. Holmes pleaded not guilty by reason of insanity. His attorneys have acknowledged he was the gunman but say he is mentally ill and was gripped by a psychotic episode when he opened fire in the theater. (AP Photo/Ed Andrieski, File)  (The Associated Press)

An unprecedented jury pool of 9,000 people has been called as lawyers begin to select 12 people to decide if James Holmes was insane when he killed a dozen people in a Colorado movie theater.

The scale of jury selection set to begin Tuesday in Denver shows how challenging it is to handle the case of a mass shooting suspect who stands trial.

The trial promises a look into the mind of Holmes, whose attorneys acknowledged was the gunman in the July 20, 2012, attack but say he was in the grip of a psychotic episode.

Holmes has pleaded not guilty by reason of insanity. If jurors find him guilty, they must decide whether to recommend the death penalty.

If found not guilty, he would be committed a mental hospital.