James Holmes, the man accused of thje Colorado theater shootings that killed 12 people and injured 70, is to change his plea to not guilty by reason of insanity.

Holmes’ lawyers said they would be filing papers to formerly change the plea when he appears on May 13.

The evidence against Holmes is overwhelming and the decision is not unexpected. The shootings, which occurred on July 20 last year, lead to charges of murder and attempted murder.

Huffington Post reports:

But his lawyers delayed entering an insanity plea for weeks, saying Colorado’s insanity and death penalty laws overlapped in a way that could severely – and unconstitutionally – hamper his defense if he did plead insanity.

The defense has asked both judges who have presided over the case to rule on the constitutionality of the laws. Both judges refused, saying the question was speculative because Holmes hadn’t entered an insanity plea. That left Holmes’ lawyers with no choice but to enter the insanity plea, then seek a ruling on the constitutionality question.

A judge in the case previously entered a standard not guilty plea for him. If a judge accepts the new plea, Holmes would be sent to the state mental hospital, where doctors would determine whether he was insane at the time of the shootings.