The suspect of the Aurora theater shooting was formally charged Monday with 24 counts of first degree murder and 116 counts of attempted first degree murder.
James Holmes also faces one count of possession of explosive device, and one sentence enhancer. Authorities say Holmes booby trapped his apartment.
The breakdown of the charges was not immediately clear.
Holmes, the former neuroscience student, is accused of killing 12 people and wounding 58 others at an Aurora movie theater on July 20. Holmes was arrested outside the Century 16 theater during a midnight showing of the new Batman movie.
Legal analysts expect his court the case to be dominated by arguments over his sanity.
Holmes was a student at the University of Colorado Denver before withdrawing last month.
Cameras were not allowed in the courtroom during Monday morning's 9:30 a.m. hearing where attorneys also argued over a defense motion to find out who leaked information to the news media.
The information included details about a package the 24-year-old former neuroscience graduate student allegedly sent to his psychiatrist at the University of Colorado Denver.
Authorities seized the package July 23, three days after the shooting, after finding it in the mailroom of the medical campus where Holmes studied. Several media outlets reported that it contained a notebook with descriptions of an attack, but Arapahoe County District Attorney Carol Chambers said in court papers that the parcel hadn't been opened by the time the "inaccurate" news reports appeared.