CENTENNIAL, Colo. (Reuters) - Defense lawyers trying to avoid the death penalty for Colorado movie massacre gunman James Holmes wrapped up their case on Friday, hoping they have convinced jurors he was legally insane when he carried out one of the worst U.S. mass shootings.

James Holmes sits in court for an advisement hearing at the Arapahoe County Justice Center in Centennial, Colorado June 4, 2013. REUTERS/Andy Cross/Pool

They concede he killed 12 people and wounded 70 when he opened fire with a semiautomatic rifle, shotgun and pistol inside a movie theater in 2012, after he had rigged his apartment with bombs. But they say he suffers schizophrenia and was not in control of his actions.

Prosecutors accuse Holmes of being a cold-blooded murderer who aimed to kill all 400 people in the packed midnight premiere of a Batman film at the Century 16 cinema in Aurora, a Denver suburb. He failed in part because the drum magazine he bought for his rifle jammed.

After playing jurors a video of the defendant naked and running head-long into a cell wall, and another of him thrashing around while splayed in restraints on a hospital bed, the defense rested.

The prosecution said it would not present any rebuttal case. Both sides will make closing arguments on Tuesday, and then the jury is expected to begin deliberating on Wednesday.

After Holmes’ attorneys wrapped up their case, some victims and relatives of those killed hugged the prosecutors.

The defense team had called a succession of psychiatrists and psychologists who studied Holmes, as well as jail staff who met him after he was arrested at the scene of the shooting dressed head-to-toe in body armor, a gas mask and a helmet.

Their star expert witness, Raquel Gur, director of the Schizophrenia Research Center at the University of Pennsylvania, spent a grueling four days on the stand defending her diagnosis that Holmes was legally insane.

“He was not capable of differentiating between right and wrong,” she said on Thursday. “He was not capable of understanding that the people that he was going to kill wanted to live.”

Gur, a noted psychiatrist and author who once examined Unabomber Ted Kaczynski and Arizona mass shooter Jared Loughner, told jurors the defendant still believes he boosted his “human capital,” or self-worth, by murdering the moviegoers.

A severe defect in his brain meant he was not to blame, she said.

HOLMES DID NOT TAKE STAND

Two court-appointed psychiatrists reached a different conclusion: while Holmes is severely mentally ill, they have told jurors, he was legally sane when he planned and carried out the massacre.

Holmes did not testify in his own defense.

Throughout the trial he has displayed almost no reaction to the parade of more than 200 victims, law enforcement officials, medical workers and other witnesses who took the stand, just a few feet in front of where he sat tethered to the floor beneath the desk used by his attorneys.

Occasionally, he turned his head to watch videos of himself played on a court television.

In his longest speech so far in open court, Holmes told Arapahoe County District Court Judge Carlos Samour on Thursday: “I choose not to testify,” and then responded with one-word answers to confirm that he understood his decision.

Holmes has pleaded not guilty by reason of insanity. If the jury agrees, he would avoid the death penalty and likely spend the rest of his life committed to the state’s mental hospital in Pueblo, 100 miles (160 km) south of Denver.

Under Colorado law, the prosecution must prove he was sane for him to be found guilty of multiple counts of first-degree murder and attempted murder. District Attorney George Brauchler attacked Gur’s testimony during lengthy cross-examination.

Suggesting she neglected important indicators of Holmes’ state of mind, he said she failed to take detailed notes, and wrote a much shorter report than the court-appointed psychiatrists.

“Why not just send in a postcard?” Brauchler asked.