Lawyers argue over Batman gunman
Two versions of the unstable mind of James Holmes were presented to a jury as lawyers revealed more about the gunman who opened fire on hundreds of moviegoers at a Batman premiere.
The lead prosecutor displayed an image of the cinema door on a TV screen as he told of a sinister but sane killer who methodically carried out the 2012 mass murder to make himself feel good and be remembered.
"Through this door is horror. Through this door are bullets, blood, brains and bodies. Through this door, one guy who thought as if he had lost his career, lost his love life, lost his purpose, came to execute a plan," said District Attorney George Brauchler, standing before a scale model of the cinema.
"He tried to murder a theatre full of people to make himself feel better and because he thought it would increase his self-worth."
Mr Brauchler said two previously secret court-ordered psychiatric exams found Holmes to be sane.
Public Defender Daniel King countered that Holmes suffers from schizophrenia, a diagnosis confirmed by 20 doctors.
Jurors must decide whether Holmes was able to know right from wrong when he slipped into the cinema, unleashed tear gas and killed 12 people and wounded 70.
He is charged with first-degree murder, attempted murder, an explosives offence and committing an act of violence for the mayhem he caused on July 20, 2012.
Holmes has pleaded not guilty by reason of insanity. His defence hopes jurors will agree and have him indefinitely committed to a mental institution. Under Colorado law, prosecutors must prove Holmes was sane in order to have him executed or spend the rest of his life in prison.
"Mental illness can sure sound like an excuse, but in this case, it's not," Mr King said. "There will be no doubt in your minds that by the end of this trial, Mr. Holmes is severely mentally ill."
Holmes sat quietly, harnessed to the floor by a cable that ran through his trouser leg, as the lawyers described his emotional rise and fall.
Defence lawyers said mental illness ran through both sides of Holmes' family, including an aunt with schizophrenic affective disorder.
Holmes attempted suicide at age 11, had "intrusive thoughts" in high school, and his mental illness "revved up" in his 20s, his lawyer Katherine Spengler said.
By the months before the shootings, Holmes was the throes of psychosis, suffering delusions that took hold of his mind and commanded him to kill.
He somehow thought slaughtering people would set things right, and was so sick afterwards that he licked the wall of his jail cell, his defence said.
His lawyers referred to the seemingly delusional rants in a journal Holmes posted to his therapist just before the shootings as proof that he had lost his mind.
Mr Brauchler pointed instead to emails Holmes sent his parents, where he seemed to communicate rationally and downplay his emotional decline.
All the while, Holmes was buying an arsenal of weapons, ammunition, tear gas, explosive chemicals, body armour and remote control detonators.
And he was going to a remote shooting range to practice what he described to an ex-girlfriend as his "evil plan," the prosecutor said.
Just a few hours into a trial expected to last four months, it became clear that prosecutors will try to prove Holmes had no excuse, and miss no opportunity to remind jurors of the lives he ended or ruined.
Holmes' victims included two active-duty servicemen, a single mother, a man celebrating his 27th birthday, an aspiring broadcaster who had survived a mall shooting in Toronto, and a six-year-old girl whose pregnant mother lost her baby and was paralysed.
"Four-hundred people came into a boxlike theatre to be entertained, and one person came to slaughter them," the prosecutor said.
Many more people would have died, but a magazine on his AR-15 assault rifle jammed, leaving 218 bullets unfired, Mr Brauchler said.
Defence lawyers said there is no need to spend months describing such horrors. They acknowledge Holmes was the killer, but his state of mind is what is in dispute.
To prove beyond a reasonable doubt that he was "NOT insane", Judge Carlos Samour Jr, told the jury, the state must show he had "a culpable state of mind".
If Holmes acted with deliberation and intent - wilfully taking actions that he knew would kill people -- then even if he had mental problems, he should be found guilty of murder, the judge said.
Insanity defences are successful in only 25% of trials in the US, even less so in murders.
Most mass shooters are killed by police, kill themselves or plead guilty.
A review of 160 mass shootings found killers went to trial 74 times, and just three were found insane.