A judge on Tuesday accepted Aurora shooting suspect James Holmes' plea of not guilty by reason of insanity, the Associated Press. Holmes is accused of opening fire in an open movie theater on July 12, 2012, killing 12 people and injuring 70. He is charged with multiple counts of murder and attempted murder, and prosecutors are seeking the death penalty. 

A thorough mental evaluation could take months.

Holmes' lawyers have long contended that their client is mentally ill, but delayed the insanity while arguing state laws were unconstitutional, the AP reported. The laws, they said, could hobble the defense if Holmes' case should ever reach the phase where the jury decides if he should be executed. The judge rejected that argument last week.

Holmes' insanity plea is regarded as his best chance of avoiding the death penalty, considering the weight of evidence against him.
The laws state that if Holmes does not cooperate with doctors conducting a mandatory mental evaluation, he would lose the right to call expert witnesses to testify about his sanity during the penalty phase of his trial. Defense lawyers argued that is an unconstitutional restriction on his right to build a defense. They also contended the law does not define cooperation, the AP reported.

Insanity is defined as the inability to distinguish right from wrong caused by a diseased or defective mind, according to Colorado law.

If jurors find Holmes not guilty by reason of insanity, he would be committed indefinitely to a state mental hospital. While unlikely, in that scenario, he could eventually be released find that his mental sanity was restored.