Holmes allegedly carried out the shooting that killed 12 and injured 58 people.

According to court documents filed by prosecutors, in March, Holmes had a conversation with a classmate at the University of Colorado-Denver about “wanting to kill people and that he would do so when his life was over”.

The student was not identified and the threats were not reported to police.

Holmes, who had been a neuroscience graduate student, failed his final exam two months before the event, and his professors were working to keep him out of their labs.

The alleged conversation occurred at the same time that police said Holmes began receiving "a high volume of deliveries" at his home and at the university.

Police haven’t said what those packages contained, but they said he ordered thousands of rounds of ammunition on the Internet.

Prosecutors made the allegation in a motion released Friday seeking access to Holmes' records from the University of Colorado Denver’s neuroscience graduate program.

Six weeks before the event, Holmes allegedly threatened his Professor around the time he failed his year-end final exam.

The nature of the threats was not elaborated in his prosecution.

Authorities say that after his arrest Holmes referred to himself as the Joker, in reference to Batman’s comic-book arch-rival.

It has been reported that Holmes’ attorney said during a previous court hearing that he suffered from an unspecified mental illness and had tried to get help.