(RJ Sangosti/Denver Post via AP Photo)

ABC News' Clayton Sandell and Carol McKinley report:

The University of Colorado psychiatrist treating James Holmes told police in June 2012 that the neuroscience student was a "danger to the public due to homicidal statements" who later began threatening her, according to newly-unsealed court documents.

Holmes is accused of opening fire just a few weeks later at an Aurora movie theater, killing 12 people and shooting or injuring 70 more.

One of the court documents detailed a conversation between Aurora police officer Will Hinton and University of Colorado police officer Lynn Whitten after the July 20 shooting. Whitten told Hinton that, in the weeks before the shooting, she was contacted by Dr. Lynne Fenton, who wanted to report that Holmes as a danger to the public because of Holmes' statements.

"Dr. Fenton advised that she had been treating Holmes, and that Holmes had stopped seeing her and had begun threatening her via text messages," Whitten told investigators.

Because of the alleged threats against Fenton, Whitten said she deactivated the card that allowed Holmes access to university buildings on July 12, according to the documents.

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The new information came to light Thursday after Arapahoe County District Judge Carlos Samour Jr. granted a request by news media companies - including ABC - to unseal about a dozen warrants and affidavits in the case.

A search warrant detailed the contents of a package found in a university mailroom that Holmes mailed to Fenton before the shooting. The package was intercepted by police and contained a brown spiral notebook with the name "James Holmes" written on it. In a space reserved for the course name, someone wrote "Of Life," investigators wrote.

Police also found $400-worth of burnt $20 bills and a sticky note "with an infinity design," according to the document.

Information in the package "may assist in determining what methods of planning were involved to carry out this crime," wrote Aurora Police Sgt. Matthew Fyles.

Another search warrant, for the first time, detailed the extensive list of items seized from the apartment Holmes allegedly booby-trapped to explode, including a Batman mask, bullets, fuses, index cards with chemical formulas, and paper targets.

Holmes was arrested just outside the theater, still wearing ballistic gear, according to one of the court documents. When a police officer asked Holmes if anyone was with him, he replied, "It's just me."

A judge has already entered a standard "not guilty" plea for Holmes, but his legal team has signaled it will pursue an insanity defense.

On Monday, prosecutors said they intend to seek the death penalty for Holmes.