Accused "Batman" theater gunman James Holmes was sane when he cold-bloodedly opened fire on a packed Colorado cinema three years ago, prosecutors said in closing arguments Tuesday.

But the troubled 27-year-old's defense team insisted he should be found not guilty due to insanity over the July 2012 shootings, which killed 12 theater-goers and injured 70 others in Aurora just outside Denver.

Wrapping up the two-and-a-half month trial, prosecutor George Brauchler ran through a blow-by-blow account of the massacre, which stunned America and reignited the country's perennial debate about gun control.

Referring to the 400 people in the theater, he said: "They came in hoping to see a story of a hero dressed in black, someone who would fight insurmountable odds in the name of justice and trying to protect others.
"Instead a different figure appeared by the screen dressed all in black. And he came there with one thing in his heart and in his mind -- and that was mass murder," the prosecutor said.

Holmes has been in custody since he was arrested outside the crowded midnight screening of "The Dark Knight Rises" on July 20, 2012.

He faces two counts of murder or attempted murder for each of the 82 victims.

Defense lawyer Daniel King said: "The fact of the matter is that when Mr Holmes stepped into that theater ... he had lost touch with reality.

"You cannot divorce the mental illness from this case, or from Mr Holmes," he said.
"The mental illness caused this to happen. Only the mental illness caused this to happen, and nothing else."

But Brauchler urged the court to "reject this claim that he didn't know right from wrong... That guy was sane beyond a reasonable doubt, and he needs to be held accountable for what he did."

Simply having a mental illness does not make a defendant insane under Colorado law, Brauchler said.

What matters, he said is "if he knows what society thinks is right or wrong."

- Grisly evidence -

Defense attorneys did not contest what happened in the massacre where Holmes lobbed smoke bomb-type devices into the theater and randomly fired weapons including an AR-15 military-style rifle, a 12-gauge shotgun and a .40 caliber pistol.
His apartment was later found to be booby-trapped with an array of homemade explosive devices, which police had to disarm before entering the dwelling.

The 49-day-long trial included weeks of grisly evidence and testimony from more than 250 witnesses.

The jury also was shown hours of videotaped interviews of Holmes by psychiatrists for the state.

Both they and two defense psychiatrists agreed the defendant struggled with mental illness.

The state's psychiatrists, however, maintained that Holmes was sane when he carried out the rampage.

Defense attorneys contended that Holmes' belief that killing people would enhance his self-worth is indicative of the profoundly delusional mental illness that barred him from telling right from wrong.
During the trial, five jurors were dismissed for various reasons from the panel of 24 jurors and alternates selected to hear the case. Only 12 jurors will deliberate in this portion of the trial.

If Holmes is found to guilty, the alternates will be recalled to hear the arguments supporting a penalty. A second jury panel would then be picked to decide a punishment.

If he is found not guilty by reason of insanity, Holmes will be confined to a state mental hospital.

To win a release, he would have to be found free of mental illness and no longer a danger to himself or to others.

Under Colorado law, he could not be retried for the criminal offenses at that time.