Prosecutors wanting to prove that a gunman methodically carried out last month's Colorado theater shooting that left 12 people dead and wounded 59 have a difficult task: If James Holmes pleads not guilty by reason of insanity, they must prove he is sane.
A court hearing Thursday will examine his relationship with a University of Colorado psychiatrist to whom he mailed a package containing a notebook that reportedly contains violent descriptions of an attack.
His attorneys say Holmes is mentally ill and that he sought help from psychiatrist Lynne Fenton at the school, where he was a Ph.D. student, until shortly before the July 20 shooting. Prosecutors allege Holmes may have been angry at the failure of a once promising academic career.
Unlike most other states where the defense needs to prove insanity, prosecutors in Colorado are the ones who have to show that a defendant is sane — without the ability of having their own experts examine Holmes.
"It's totally subjective," said Marcellus McRae, a former federal prosecutor now in private trial attorney in Los Angeles. It's not like proving somebody pulled the trigger. That's objective."
Authorities have said that Holmes meticulously stockpiled ammunition and other gear and booby-trapped his apartment to kill, suggesting that he knew what he was doing.
With the burden on prosecutors, those details don't matter, prosecutors say.
Whether he pleads guilty by reason of insanity, the case against Holmes promises to focus on his mental health.
Insanity is unlike the mental competency argument used for Jared Loughner, who ultimately pleaded guilty in federal court to the 2011 Arizona shooting that killed six people and wounded 13 others, including then-Rep. Gabrielle Giffords.
Mental competency involves whether a defendant is aware of what's happening in court and can assist his or her attorneys with a defense. In Loughner's case, he received treatment, became competent and entered his plea.
In an insanity defense, a defendant is deemed not guilty because he didn't know right from wrong and is therefore "absolved" of the crime, said Jefferson County District Attorney Scott Storey, who recently lost an insanity case.
If Holmes is found sane and goes to trial and is convicted, his attorneys can try to stave off a possible death penalty by arguing he is mentally ill. Prosecutors have yet to decide whether to seek the death penalty.
Insanity cases depend on a court-ordered evaluation by state psychiatrists and up to two additional state evaluations requested by defense attorneys or prosecutors and approved by a judge.
In about 40 states and in federal court, the burden of proof is on the defense, which must prove that a client is insane.
U.S. defense attorneys say the system is fine because a defendant gives up certain rights when pleading insanity, including the right to remain silent. Once a defendant enters his plea, the court orders an independent evaluation by a state doctor, from whom findings of insanity in criminal cases are rare, said Scott Robinson, a Denver criminal attorney.
The uphill battle for prosecutors is compounded by the incomprehensible nature of the crime.
"What do you think the popular mindset is about somebody coming into a theater and killing a bunch of people? That he's crazy," McRae, the former federal prosecutor said. "If they (prosecutors) didn't have to prove insanity, this wouldn't be much of a trial at all."