DENVER, United States, Nov. 8 (Xinhua) -- Presiding judge of the Colorado theater shooting case Carlos Samour ordered Friday to jump the jury pool from 6,000 to 9,000, making it the largest in the history of the United States.
It will be much easier to call off prospective jurors who are not needed than it will be to adjust if there are insufficient prospective jurors, Samour explained.
Jury selection will begin on Jan. 20 and could last months.
Samour told attorneys to be ready to give opening statements for the actual trial in early June.
Accused shooter James Eagan Holmes is pleading not guilty by reason of insanity to killing 12 people, 166 counts of attempted murder, and injuring 70 in an attack at the midnight premiere of a Batman movie in Aurora, Colorado on July 20, 2012.
Holmes' mental state at the time of the shooting will be the primary focus of the trial.
Prosecutors are seeking the death penalty against Holmes, and the trial is expected to take months.