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Brennan Linsley, Associated Press
A sheriff's deputy walks the grounds of the Arapahoe County District Court, where the trial of Aurora movie theater shooter, James Holmes, continues, Wednesday, July 8, 2015, in Centennial, Colo. Prosecutors are tearing into the testimony of a second defense expert who concluded the shooter was so mentally ill that he couldn't tell right from wrong when killed 12 people and injured 70 during a packed midnight movie premiere three years ago.

CENTENNIAL, Colo. — The final days of testimony in the Colorado theater shooting trial are presenting jurors with the pivotal question they'll have to decide — whether to believe psychiatrists who say shooter James Holmes was sane, or whether to believe psychiatrists who say he was insane when he opened fire in a crowded movie theater in 2012.

Holmes' defense is wrapping its case with a nationally known schizophrenia expert who, on Thursday, defended her conclusion that Holmes was so delusional that he was unable to tell right from wrong during the 2012 attack that killed 12 people and injured 70. Closing statements are expected next week.

Dr. Raquel Gur saw Holmes for 28 hours in six separate meetings. She leads the Schizophrenia Research Center at the University of Pennsylvania and is considered the star witness for the defense.

She testified Thursday that Holmes didn't hate the people he shot on July 20, 2012, but was suffering delusions that killing others would increase his self-worth.

"He did not feel angry," Gur said. "He wanted to stop the thoughts that had bothered him for years."

But prosecutors hammered at Gur's report, accusing her over more than two days of cross-examination of everything from bad grammar to being errant by not asking certain follow-up questions or recording her interviews.

The psychiatrist's exchanges with District Attorney George Brauchler went from testy to hostile Thursday.

Brauchler grilled Gur on leaving out some details from her written account of her Holmes interviews.

"What you want to say is, 'I picked and chose what to put in the report,'" Brauchler said.

An exasperated Gur replied, "Of course, I wrote the report! But what I put in the report was what I was trained to do."

Defense attorney Daniel King characterized the prosecutor's attack as nitpicking over grammar and punctuation but said the substance of Gur's report stands. He asked if she would risk her reputation by giving jurors false information.

"Absolutely not," she replied.

The whole case depends on how reliable jurors find the more than 10 psychiatrists who testified at some point about Holmes' mental state before and after the shootings.

Holmes has pleaded not guilty by reason of insanity, and in Colorado prosecutors must prove beyond a reasonable doubt that Holmes was sane when he committed his crimes.

During a break in the proceedings, Holmes seemed relaxed, smiling and chatting quietly with two of his attorneys.

Earlier Thursday, Judge Carlos A. Samour Jr. ruled that jurors would not see a video of Holmes talking about being afraid of "shadows" he saw while at a hospital four months after the attack. Holmes' attorneys wanted to show jurors the video, but Samour ruled it inadmissible because prosecutors wouldn't be able to cross-examine Holmes.