The jury in the Colorado theater shooting trial is deliberating for a second day over whether James Holmes was legally insane when he opened fire on a crowded movie premiere.

Holmes' killed 12 people and injured 70 in the July 2012 attack in what his attorneys describe as a severe psychotic breakdown. Jurors returned Thursday to consider whether prosecutors have met their burden in proving Holmes was capable of knowing right from wrong and therefore legally sane under Colorado law.

Jurors must pore over thousands of pieces of evidence and 11 weeks of testimony to make their decision.

They requested a whiteboard Wednesday. They also asked for an index to the mounds of evidence left for them in the jury room, but the judge declined.