Prosecutors in the US are expected to file formal charges against the student accused of killing 12 people and injuring 58 others in a cinema gun rampage.
Lawyers will also argue at today’s hearing in Colorado over a defence motion to find out who leaked information to the news media.
The information included details about a package former neuroscience graduate student James Eagan Holmes allegedly sent to his psychiatrist at the University of Colorado Denver.
Legal analysts expect the case will be dominated by arguments over the 24-year-old defendant’s sanity.
Holmes allegedly began stockpiling equipment for his assault four months ago, well before the shooting spree just after midnight during a showing of the new Batman film The Dark Knight Rises in the Denver suburb of Aurora.
He was arrested by police outside the cinema.