U.S. legal analysts say lawyers for the man, James Holmes, accused of killing 12 people at a movie theater in Colorado could mount an insanity defense.
A defendant is typically found not guilty by reason of insanity when the defense proves he or she did not know right from wrong at the time of the crime.
In federal court and most state courts, the defense must prove insanity by "clear and convincing evidence."
But in some states, including Colorado, the burden of proof is on the prosecutors, who must prove the suspect was sane at the time he committed the offense.
Lisa Wayne, the immediate past president of the National Association of Criminal Defense Lawyers (NACDL) and a practicing Colorado defense attorney, says despite the burden on prosecutors, Colorado is one of the tougher states for a defendant to claim insanity. She says even in Colorado, the defense team must raise credible evidence.
"What usually happens in these kind[s] of cases is that the conduct by the defendant is dissected by both sides. The government will look at the weeks before the conduct occurs and sometimes the weeks after. But what led up to the conduct? Can we show that, in fact, this is someone who really was planning and there was premeditation and those kind[s] of things? Or is there really a likelihood that this person has a mental disease or defect? That's usually the language that's used," explained Wayne. "So the mental health part of it is very important in terms of lining up credible psychiatrists, doctors who can really, in a credible fashion, say this defendant is just suffering from an extreme mental illness."
Wayne says misunderstandings about the insanity defense are common. "Most jurors and most people in the public, when you say someone was so mentally ill or they were insane, they want to see someone who is out of it, who is, you know, literally their hair is a mess, they're slobbering. It's the stereotypical picture of what we believe someone who is insane looks like, and that's not necessarily true. So it's a tough burden, and you don't see it occurring very much in the criminal justice system," she said.
Even though people found insane are acquitted, Wayne says that does not make the defense an "excuse" or "easy way out," nor does it mean the defendants are not taking responsibility for their crimes. She says the individuals are committed to state hospitals, where many spend several years to the rest of their lives.
"What the public doesn't know is spending a life sentence in a state hospital for many defendants is far worse than going to a prison setting. It has not moved forward in this country very much, in terms of what you see in [the 1975 film] One Flew over the Cuckoo's Nest. Our state hospitals are in a deteriorated, pretty bad shape because of funding in this country," Wayne said. "So it's not a pleasant place to go. It's not better. It's not easier. And in fact, many people, many defendants, would say, 'I'd rather be in jail.'"
One of the most high-profile acquittals by reason of insanity was that of John Hinckley, who, in 1981, shot then-U.S. president Ronald Reagan in an assassination attempt. The Hinckley verdict prompted a widespread outcry, leading the federal government and many states to change their laws to shift the burden of proof of insanity to the defendant.
Wayne says more than 30 years later, Hinckley is still in a state institution.