IF THE Batman movie killer doesn't get the death penalty, then the death penalty is as good as gone for the state of Colorado.
That's the view of informed commentators as suspect James Holmes, was due in court later today.
Holmes faces a dozen first-degree murder charges, according to a July 26 court filing.
Twelve people died and at least 58 were injured when cinema goers were attacked during a midnight showing of The Dark Knight Rises.
Premeditated murder of multiple victims can be punishable by death in Colorado.
A mother whose six-year-old daughter was killed in the cinema and who was seriously injured herself lost her unborn baby over the weekend.
Ashley Moser survived the massacre, but is believed to have been paralysed after being shot. She lost her unborn child after undergoing surgery related to her injuries.
Her six-year-old daughter, Veronica, was shot dead in the attack.
"Holmes is looking at well over 1,000 years in prison and I doubt he will live that long so this is all about the death penalty," said Craig Silverman, a former chief deputy district attorney in Denver who is now in private practice.
"If the death penalty is not obtained against Holmes, that would represent the effective end of capital punishment in Colorado."
The shooting in Aurora, a suburb of Denver, was the deadliest in Colorado since the Columbine High School massacre in April 1999 and the worst mass shooting in the US since November 2009, when 13 people were killed at Fort Hood in Texas.
An insanity defence by Holmes seems probable, as well as a claim that he's incompetent to stand trial, Silverman said.
However, such a defence, coupled with hundreds of charges, could result in a "nightmare prosecution," Silverman said.
Carol Chambers, the district attorney for Arapahoe County, will formally charge Holmes at a hearing today in state court in Centennial, Colorado.
She said after the shooting that a decision on whether her office would seek the death penalty is months away.
"I don't think this is a slam-dunk case," Silverman said. "The elements of first-degree murder are clearly there and there is no question about cause of death or who did it.
"However, once the defence presents evidence of insanity, the prosecution has to prove beyond a reasonable doubt that Holmes was not insane," Silverman said. "That can be tough."
The office of Colorado State Public Defender Douglas K Wilson is representing Holmes. Wilson didn't respond to a call seeking comment on a judge's July 26 order that cited prosecutors as saying Holmes may face 12 counts of murder.
Holmes's lawyers won't assert a defence, including any possible insanity defence, until after the formal charges are filed.
Holmes allegedly bought a ticket for the Batman showing, entered the cinema and watched the film for a while before propping open an exit door and leaving, according to police.
He went to a white Hyundai parked outside, put on a helmet and ballistic vest, armed himself and returned to the cinema, police said.
Police apprehended him behind the building, located in a shopping mall, after the first 911 call at 12:39am.
Three weapons were retrieved at the scene. A fourth, a .40 calibre Glock handgun, was found in Holmes's car.
During an initial court appearance on July 23, Holmes appeared at times lethargic and at others distracted.
His hair dyed orange and dressed in red prison clothing, Holmes didn't enter a plea or speak.
At times he opened his eyes wide and blinked rapidly.
Holmes allegedly referred to himself as "the Joker," a Batman villain, as he was being arrested.
Holmes, whose apartment was booby-trapped with explosives, acted bizarrely hours after his arrest and used evidence bags as hand puppets.
Those actions don't necessarily point to insanity, Silverman said.
"He may well be faking it," Silverman said. "Those eye movements in the courtroom are the kind of acting any one of us could do.
"It was not evidence that he's insane."