The third day of jury selection has begun in the Colorado theater shooting trial of defendant James Holmes.

An unprecedented 9,000 potential jurors were initially summoned in the case and the process of choosing a jury is expected to take months.

Judge Carlos Samour has excused a number of jurors so far, including one woman on Thursday who worried that her panic attacks would be heightened by the case.

Hundreds more people will fill out a jury questionnaire during the day.

Holmes has pleaded not guilty by reason of insanity to charges that he killed 12 people and injured 70 others when he opened fire on a packed suburban movie theater in 2012.

If convicted, Holmes could face the death penalty.