Jury seated in death penalty trial of Colorado theater shooter James Holmes

April 13, 2015: People enter and leave the Arapahoe County District Court in Centennial, Colo.

April 13, 2015: People enter and leave the Arapahoe County District Court in Centennial, Colo.  (AP Photo/Brennan Linsley)

The jury was seated Tuesday in the death penalty trial of Colorado theater shooter James Holmes, who is charged with killing 12 people and injuring 70 more in the July 2012 attack.

The seating comes after one of the largest and most complicated selection processes in U.S. history. Selection began on Jan. 20.

The 12 jurors and 12 alternates, made up of 19 women and 5 men, were picked a day after remaining candidates were questioned as a large group Monday.

There were at least six Batson challenges during the peremptory strikes on Tuesday. Batson challenges dispute a strike on the grounds that it appears discriminatory.  The majority of the Batson challenges focused on whether the prosecution was trying to remove Hispanics from the pool.  However, the judge sided with the prosecution and did not overrule any of the challenged strikes.

Once the jury was selected, the judge also heard a motion for change of venue.  The judge called the motion "untimely" and ruled against change of venue. 

About 9,000 prospective jurors initially were summoned in what experts called the nation's biggest-ever jury pool, The Associated Press reported. They spent weeks filling out lengthy written questionnaires.

Hundreds were then asked to return for one-on-one questioning, where defense attorneys, prosecutors and the judge questioned them, sometimes for hours, about their views on the death penalty, mental illness and other aspects of the criminal justice system.

Opening statements are scheduled for April 27 at 9 a.m. MT.

Holmes’ defense attorneys don't dispute that he pulled the trigger when he slipped into the theater during a showing of "The Dark Knight Rises," but say he was in the grips of a psychotic episode when he slipped into the theater and opened fire while dressed from head to toe in combat gear.

Prosecutors insist Holmes was sane and will ask jurors to convict him and sentence him to death.

If the jury finds Holmes was legally insane at the time of the attack, he would be committed indefinitely to the state psychiatric hospital. If the jury convicts Holmes, the only other option other than a death sentence is life in prison.

Many potential jurors were excused when they said they already had an opinion on Holmes' guilt or were morally opposed to the death penalty.

Still others were dismissed because of personal connections to the shooting, including people who had friends or family in the packed theater that night, or who knew some of the hundreds of first responders who rushed to the scene.

The Associated Press and Fox News’ Faith Mangan contributed to this report.