[Updated at 4:00 p.m. ET]
CENTENNIAL, Colo.—Prosecutors on Thursday surrendered their battle for a notebook Colorado murder suspect James Holmes sent to his psychiatrist the day before he allegedly killed 12 and wounded 58 in an Aurora movie theater.
The notebook reportedly contains descriptions of a violent attack. Prosecutors considered it potential evidence, but Holmes' defense team had maintained it fell under doctor-client privilege.
But in court on Thursday, prosecutors justified their decision to give up the fight by saying that they'll likely get to see the notebook if Holmes pleads not guilty by reason of insanity. Continuing their push, they said, would only drag out the case.
Holmes allegedly mailed Dr. Lynne Fenton, a University of Colorado psychiatrist he had seen, a package the day before the July 20 shootings.
Holmes' defense team will now get to review and photograph the notebook, but only under court and police supervision.
Holmes was arrested two months ago behind an Aurora movie theater after the deadly rampage during a premiere showing of Batman "The Dark Knight Rises." The melee is among the worst mass shootings in modern-day American history.
The 24-year-old suspect was in court on Thursday, but appeared different than how he looked at the time of his arrest and initial hearings. The long, cartoonish red-orange hair is gone, and is now a closely cropped brown. Holmes seemed alert in court. He appeared to follow the conversation during the hour-long hearing, but he did not speak.
The Associated Press said Holmes appeared more animated during the hearing.
"He smiled and glanced around the courtroom, looking at his lawyers and reporters covering the hearing," an AP reporter wrote. "He appeared to be moving his mouth but not actually talking."
The judge on Thursday also approved the district attorney's request to tack on 10 additional charges of criminal intent to commit murder in the first degree. Names of the victims were redacted from the court filing, but prosecutors wrote, "the facts warrant the additional charges."
The former Ph.D neuroscience student now faces a total of 152 criminal complaints, including 24 counts of first-degree murder (dual charges include premeditated and without remorse).
[Yahoo News staffer Tim Sprinkle contributed to this report from Centennial, Colo.]