Jury selection for the trial of James Holmes, who allegedly killed 12 people at a theater in Aurora, Colorado and injured dozens of others in July 2012, will begin on Tuesday.

According to 7ABC in Denver, the Arapahoe County Court sent summons to 9,000 potential jurors. The first group will be in court on Tuesday and attorneys have to whittle the jury pool down to 12 jurors and 12 alternates.

Holmes could possible attend the jury selection process after the judge ruled that he could attend.

While Holmes’ attorneys have said that Holmes was the man who opened fire at the movie theater on July 20, 2013 during a The Dark Knight Rises screening, Holmes has pleaded not guilty by reason of insanity, reports KKTV.

District Attorney George Brauchler is the prosecutor. He will have to prove that Holmes was both guilty and sane during the shooting. The judge will also tell jurors that the state is seeking the death penalty.

7ABC reports that after filling out a questionnaire, the potential jurors will have to be individually questioned in February through May. The final part of the process that will decide the jury is group questioning in May or June.

If Holmes is not convicted, he could be committed to a mental hospital.