The suspect in the Batman movie shooting case mailed "burnt currency," along with a notebook, to his psychiatrist before the attack.

He threatened a professor and was banned from a university campus before withdrawing from its neuroscience graduate program. His defence team has added a psychiatrist.

Those were the few tidbits of information in hundreds of pages of heavily-redacted court documents released Friday (local time), which serve as the best chance the public has to understand what happened before James Holmes allegedly opened fire at a midnight screening of the new Batman movie more than two months ago.

The documents shed little light on Holmes' possible motives or whether the university ignored warning signs about him.

That's partly because Arapahoe County District Judge William B. Sylvester continued to keep under seal the key documents in the case - the affidavit that lays out prosecutors' case against Holmes, and the search warrants that allowed them to gather evidence against him.

Holmes, 24, faces 152 charges in the July 20 shooting that killed 12 people and injured 58 others.

Some of the documents are entirely blacked out. In others, Sylvester's rulings on legal disputes, references to years-old case law and even copies of newspaper articles are redacted, along with information about the investigation.

The documents do shed a little more light on one of the main disputes in the case - Holmes' threats against a professor, possibly the university psychiatrist, Dr. Lynne Fenton, who has testified that she contacted campus police after her last meeting with Holmes June 11. Fenton, who testified August 30, said she went to police to gather more information and communicate her "concern."

She did not refer to her concern as a threat.

Prosecutors contended that Holmes was barred from campus after making the threats. The University of Colorado has said that Holmes was denied access to nonpublic buildings on campus because he withdrew as a neuroscience graduate student, not for safety reasons.

A university spokeswoman did not return a call for comment on Friday. The university has previously refused to comment on how it handled Holmes, citing a gag order that Sylvester imposed. Before the gag order, university officials said their police force had no contact with Holmes and that the chief of the department knew nothing about him.

The defence team sought sanctions against prosecutors for contending Holmes had been barred from campus, arguing that the false statements could contaminate the jury pool. But Sylvester shot that down, ruling the statements were within legal bounds.

Defence attorneys did not return a call for comment Friday.

The most legally significant disclosure Friday was the inclusion of the psychiatrist on Holmes' defence team. Holmes' attorneys have said he is mentally ill.

"This is unusual in a normal case, but not surprising in this case," said criminal trial lawyer Dan Recht, former president of the Colorado Criminal Defence Bar. "Presumably he's (the psychiatrist) the one who is going to opine on whether Holmes is insane or not.

"It's a foregone conclusion that the defence will plead not guilty by reason of insanity."

Other documents likely contain new information, but are blacked out. For example, in one pleading, attorneys describe how law enforcement handled the package that Holmes sent Fenton, which was discovered four days after the attack and also after Holmes allegedly booby-trapped his own apartment.

Authorities were so worried the package was also rigged that they X-rayed it and had a technician in a protective suit open it. What investigators saw when they realized the package was not dangerous, however, is redacted. All that is legible in the documents is a reference to the package containing a notebook with a post-it note and "burnt currency."

The records also show that authorities obtained text messages that Holmes sent a classmate. The documents do not say what those texts discussed.

In court, prosecutors suggested Holmes was angry at the failure of a once promising academic career and stockpiled weapons, ammunition, tear gas grenades, and body armour as his research deteriorated and professors urged him to get into another profession. Chief Deputy District Attorney Karen Pearson said Holmes failed a key oral exam in June, was banned from campus and began to voluntarily withdraw from the school.

Documents filed in the case from now on will be public, unless prosecutors or defence attorneys ask they not be released.

- AP