James Holmes considering insanity plea for Aurora theater shooting

The man accused of the Aurora theater massacre may plead not guilty by reason of insanity, according to documents filed by his attorneys in court.

The 25-year-old is due to be arraigned in 10 days for opening fire on a crowd of moviegoers on July 20, killing 12 and injuring dozens. 

Motions filed in court Thursday by his attorneys alluded to an insanity plea, and questioned the constitutionality of several aspects of the state’s insanity defense laws for defendants, the LA Times reported.

It included the issue of the phrase "mental condition", which appears in the statute.

"Mr Holmes is considering entering a plea of not guilty by reason of insanity…but he cannot intelligently decide how to proceed, until this Court rules upon certain legal issues related to the entry of such a plea and advises Mr Holmes and counsel of the consequences of such a plea," his defense counsel wrote in a documet to the court. 

Although Holmes' attorneys have broadly hinted previously that he was considering a mental-health defense, the five motions filed in court Thursday are the first indication of the strategy they might adopt, the Denver Post reported.

More from GlobalPost: Colorado shooting suspect James Holmes to face trial, judge says

At a pre-trial hearing in January, prosecutors told the court Holmes amassed an arsenal of weapons ammunition and had planned the massacre by casing out the theater at least three times before the shooting, USA Today reported.

Cellphone pictures taken hours before the massacre show Holmes grinning and sticking out his tongue wearing black contact lenses.

Arapahoe County prosecutors have not yet responded to the motions, but it could delay the start of the trial by several weeks, and it is unclear whether Holmes' arraignment, scheduled for March 12, will go ahead.