Defendant James Holmes is due for his arraignment on Tuesday. Court documents have indicated that the Aurora shooting suspect may enter a plea of not guilty by reason of insanity for the shooting rampage at a movie theater on July 20, 2012, leaving 12 people dead and injuring 58 others, according to CNN.
Prosecutors have yet to indicate whether they will pursue the death penalty against Homes.
"There are a few reasons they wouldn't go for the death penalty; the most important one being his mental state," David Beller, an attorney not connected to the case, told CNN. "The Supreme Court, and really society, has been very clear: 'We don't execute people who are mentally ill.'"
Family members and friends of victims of the Aurora shootings dispute the claims that Holmes is insane. Federal agents said Holmes began buying guns in May 2012, two months before the attack, allegedly building an arsenal of two Glock handguns, an AR-15 rifle, a shotgun and 6,295 rounds of ammunition, according to police reports.
In addition, authorities contend he deliberately dyed his hair fiery orange to resemble "the Joker," and apparently visited the AMC movie theater often, taking photographs of hallways and doors, up to two weeks prior to the shooting.
"He wanted to kill all of them, and he knew what he was doing," prosecutor Karen Pearson said, according to Yahoo.
An insanity defense refers to "a person who is so diseased or defective in mind at the time of the commission of the act as to be incapable of distinguishing right from wrong with respect to that act is not accountable," according to the Colorado Bar Association.
Holmes is charged with a total of 166 counts of murder, attempted murder and other charges. To coincide with his crimes, authorities said he booby-trapped his apartment with explosives, then traveled to the movie theater armed with four weapons, tear gas and body armor planning to kill audience members during a screening of "Batman: The Dark Knight Rises."
Witnesses said Holmes roamed the theater on July 20, shooting randomly at people.
At his preliminary hearing in January, police who responded described Holmes, dressed in body armor, standing outside, seeming "detached from it all," according to Officer Jason Oviatt and reported on CNN.
