James Holmes is going to plead not guilty by reason of insanity to the killings of 12 people and wounding of dozens more in the Aurora movie theater shootings.
His lawyers wrote in a court filing Tuesday that he intends to enter the plea during his next court hearing on May 13.
Prosecutors announced in April they will seek the death penalty against Holmes.
A few things have to happen in the case now.
A judge already entered a not guilty plea on behalf of Holmes at arraignment over the objection of his attorneys.
The judge responded to the filing by saying Holmes' attorneys will have to show "good cause" to change the plea. See the judge's order.
His lawyers will have to show the court why Holmes should be allowed to change to an insanity plea.
If the judge grants the request to allow the change, Holmes will then undergo a mental health evaluation. That is something that could take several months to complete.
Holmes faces 166 counts of murder, attempted murder and other crimes for the attack at the Century Aurora 16 theater at the premiere of the Batman movie "The Dark Knight Rises" July 20, 2012.