Updated at 9:22 p.m. ET
(CBS/AP) DENVER - The former graduate student accused in the deadly Colorado movie theater shooting was being treated by a psychiatrist at the university where he studied, a revelation that adds to suspicions that his life was in turmoil in the year before the rampage.
Attorneys for James Holmes, 24, made the disclosure in a court motion Friday as they sought to discover the source of leaks to some media outlets that he sent the psychiatrist a package containing a notebook with descriptions of an attack.
The motion said the leak jeopardized Holmes' right to a fair trial and violated a judge's gag order.
The lawyers added that the package contained communications between Holmes and his psychiatrist that should be shielded from public view. The document describes Holmes as a "psychiatric patient" of Dr. Lynne Fenton.
A group of 21 news organizations, including CBS News, is asking a judge to reverse his order sealing court records in the case.
The motion did not reveal when Holmes began seeing Fenton or whether he was being treated for a mental illness. Legal analysts expect Holmes' attorneys to use an insanity defense at trial. Holmes is scheduled to be arraigned Monday.
Calls to Holmes' lawyer and the state public defender's office were not immediately returned, as was a message left with Fenton's office. The University of Colorado's website identifies her as the medical director of the school's Student Mental Health Services.
A spokeswoman for the Arapahoe County prosecutor's office declined comment.
In the week since the attack, few details have emerged about Holmes' life since June 2011, when he enrolled in a prestigious doctoral program in neuroscience at the University of Colorado-Denver Anschutz medical campus. He left without explanation in June. University officials have refused to disclose much more about Holmes, citing an order from the judge barring it from releasing information that would "impede an ongoing investigation." Staff, professors and classmates have been mum about his life at the school.
Previously, CBS News senior correspondent John Miller reported that U.S. postal inspectorsthrough the mailboxes near Holmes' home looking for letters and packages he might have sent out. They didn't find any, but that's because the package had already been sent before the shooting.
On Monday afternoon, investigators scoured the mailroom at the University of Colorado-Denver/Anschutz Medical Campus and found what they'd been searching for: a piece of mail from the suspect in the Aurora, Colo., shooting that killed 12 people and injured 58 at a midnight screening of the new Batman film last week.
Before opening it, the sheriff's bomb squad handled it with a robot and took an X-ray, just in case there were explosives inside.
Sources told Miller the letter was from a pent-up Holmes to one of his professors. In it, he talked about shooting people and even included crude drawings of a gunman and his victims.
It's unclear if it was sent before the attack at the July 20 midnight showing of "The Dark Knight Rises" that left 12 dead and dozens of others injured.
Holmes' appearance at his first court hearing on Monday stunned the victims' families and fueled speculation about the state of his mental health. His hair dyed a shocking comic-book shade of orange-red, he looked sleepy and, at times, inattentive.
Prosecutors said they didn't know if he was being medicated.
The motion Friday, however, was the first confirmation from the defense that Holmes was seeing a psychiatrist and that he had sent a package to the doctor.
Authorities said Holmes legally purchased four guns before the attack at Denver-area sporting goods stores a semiautomatic rifle, a shotgun and two pistols. To buy the guns, Holmes had to pass background checks that can take as little as 20 minutes in Colorado.
Federal law bars from purchasing firearms people who have been found mentally defective by a judge or who have been committed to a mental health institution, said Benjamin Van Houten of the Law Center to Prevent Gun Violence.