Arapahoe County Sheriff's Office via AFP - Getty Images

James Eagan Holmes is scheduled to be arraigned March 12 in the July 2012 Colorado theater shootings that killed 12 people.

James Eagan Holmes, the man charged with killing 12 people and wounding 58 others in a crowded Colorado movie theater last year, may seek to plead not guilty by reason of insanity, his lawyers indicated in court documents made public Friday.

Holmes, 25, allegedly stormed a theater in Aurira, Colo., showing the premiere of "Batman: The Dark Knight Rises" on July 20 and opened fire with an armament of legally acquired weapons. He is charged with 166 counts of murder, attempted murder and other offenses. 

Prosecutors still haven't said whether they intend to seek the death penalty for Holmes, who is scheduled to be arraigned March 12, and Friday's filing indicates that the lack of certainty is complicating his defense.

"Mr. Holmes is considering entering a plea pursuant to (the Colorado law governing insanity pleas), 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.

In five filings, Holmes' lawyers ask the court to declare parts of that law unconstitutional. Specifically, it argues that sections governing when a defendant may waive his right to remain silent and whether he must reveal confidential medical information are unconstitutionally vague.

Holmes' attorneys have previously said he suffers from mental illness, and he is known  to have seen a psychiatrist at the University of Colorado Medical School before he dropped out a month before the shootings.

Only one person has been executed in Colorado since it legalized capital punishment in 1976.

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This story was originally published on Fri Mar 1, 2013 6:30 PM EST

AFP - Getty Images file

James Eagan Holmes is accused of opening fire July 20 on a crowded theater at a showing of "Batman: The Dark Knight Rises" in Aurora, Colo., killing 12 people.

Aurora shooting suspect James Eagan Holmes was briefly in a romantic relationship with a fellow graduate student, but she was out of the country when the theater massacre took place, according to records released Wednesday by the University of Colorado.

The university released more than 1,500 emails from Holmes’ accounts, and another 2,300 emails in its system that that referenced Holmes — a response to Freedom of Information requests from KUSA, an NBC affiliate in Denver, and other news outlets.

About 1,000 of the emails that mention James Holmes were redacted, the Denver Post noted, and at least 1,200 emails written by Holmes were not released because the university deemed them private student records, and thus not subject to disclosure Family Educational Rights and Privacy Act, KUSA reported.

The messages provide some new details about Holmes and the university's response to the tragedy, in which the former neuroscience student is accused of opening fire on a crowd at the July 20 premiere of "Batman: The Dark Knight Rises" in Aurora, Colo., killing 12 people and wounding 58.

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Among the revelations contained in the newly released documents was that Holmes had been romantically involved with another student in his graduate program, referenced in an email apparently written by an instructor or another student.

"Yeah, he was a grad student here, and, it turns out, had a brief romantic relationship with one of the grad students in my program last fall," the mail reads. "She, fortunately, it turns out is in India right now. She knows, and is pretty freaked out."

In an email, Holmes asks to participate in an fMRI study — which stands for "functional magnetic resonance imaging." In another he expresses interest in a family-medicine residency position.

Some of the email is the missives that flew back and forth as the details of the Aurora shooting emerged, with writers expressing horror and dismay.

"[Holmes] could have done this on campus instead of the movies," wrote one research assistant.

Once the university realized Holmes was a student of theirs, they instructed staff and students to not post on Facebook or Twitter about him.

Prosecutors pursue two-track strategy against James Holmes in Colorado massacre

What is not included in the emails are those that deal with Holmes' mental health history, the crime and any personal communication involving Holmes.

KUSA continues to review the emails. Many of the pages have the phrase "Privilege — Redacted in Full."

Holmes was arrested in the parking lot of the Century Aurora 16 theater shortly after the shootings and told officers his apartment contained explosives, police said. That information prompted evacuation of Holmes' apartment building and those surrounding it until law enforcement teams could disarm the jumble of wires and explosive devices set to detonate by trip wires.

He is facing two sets of first-degree murder charges for each of the of 12 deaths. He is also charged with 116 counts of attempted murder, as well as one count of illegal possession of explosives, according to court documents.

NBC News' M. Alex Johnson contributed to this report.

Slideshow:

File - Ted S. Warren / AP

A memorial to the theater shooting victims went up July 24 in Aurora, Colo.

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