Newly released court papers say that the suspect, James Holmes, was seeing a schizophrenia specialist.
Holmes went on a shooting spree during the premiere of The Dark Knight Rises in Aurora, Colorado, on July 20.
The legal papers lodged by Holmes’s lawyers said he was being treated by a psychiatrist at the University of Colorado, where he had studied neuroscience.
The court motion was seeking the source of a media leak.
This week, an unidentified official told US media that Holmes had sent a package to his psychiatrist containing a notebook which had descriptions of an attack in it.
There were conflicting reports about whether the package reached the school in time to potentially prevent the massacre, but officials remained tight-lipped due to a strict gag order imposed by the judge overseeing the case.
Holmes’s lawyers said this violated a court gagging order and put a fair trial in serious jeopardy.
“The government’s disclosure of this confidential and privileged information has placed Mr Holmes’s constitutional rights to due process and a fair trial by an impartial jury at serious jeopardy,” the attorneys wrote.
In a preview of likely battles to come, the defence lawyers also argued that the contents of the package should not be used as evidence because communications between Holmes and his psychiatrist, Lynne Fenton, were “protected”.
The filing said Holmes was Ms Fenton’s psychiatric patient.
Ms Fenton teaches at the University of Colorado’s medical school and heads student mental health services, in addition to conducting research in schizophrenia and other mental illnesses.
But the document did not indicate how long Holmes had been seeing Ms Fenton or whether she was treating him for mental illness.
Prosecutors rebuffed the defence motion, arguing that news stories about the package contained significant “factual errors” and that there was no evidence the government was responsible for the leaks.
The reporting mistakes may indicate that reporters are “getting information from hoaxers, fraudsters or maybe from nobody at all by creating fake ‘law enforcement sources’ out of whole cloth,” prosecutors wrote.
Holmes, who was studying neuroscience in a doctoral program at the university, is expected to be formally charged at his next court hearing on Monday.
As fisrst appeared on ABC Online, 29 July 2012