James Holmes' attorneys have filed a document saying he intends to enter a not guilty by reason of insanity plea Monday.
The document is titled "Notice of intent to tender plea of not guilty by reason of insanity."
Holmes, a 25-year-old San Diego Native and former University of Colorado graduate student in neuroscience, is charged with 166 counts in the July 20 massacre. The shooting, which occurred during a showing of the "The Dark Knight Rises," left 12 moviegoers dead and injured 70 people.
Aurora Police officers who testified in Holmes' preliminary hearing revealed that the suspected shooter was arrested behind Theater 9. He was spotted wearing body armor and he had a gas mask.
Holmes was allegedly armed with a rifle, two handguns, a shotgun and tear gas. According to testimony from an ATF agent, he also had several varieties of high-capacity magazines.
Recent court documents from the prosecution indicated they've provided the defense with more than 37,000 pages of documents related to the case and 436 optical storage disks of various formats. Those disks contain audio, video, photographs, business records, computer forensic reports and laboratory files.
There is so much evidence in the case that, for the first time ever, the Aurora Police Department has assigned a detective to work full-time organizing the information.
Included in that evidence are photographs downloaded from Holmes' smartphone and introduced as evidence at his preliminary hearing. Some of the photos showed an orange-haired Holmes posing with several of the weapons allegedly used in the shooting. Other photos taken in the weeks leading up to the shooting showed the interior and exterior of the theater.
Not included in the evidence, however, is the notebook that Holmes mailed to his psychiatrist. The contents of the notebook have never been confirmed, although a Fox News reporter has published what she says two sources told her about the contents.
The notebook has been protected up to this point as a matter of doctor-patient confidentiality, but could become evidence if the not guilty by reason of insanity plea is entered and excepted by the court.
The prosecution declared on April 1 they would seek the death penalty.
Monday's hearing is scheduled for 9 a.m.