DENVER (Reuters) - Prosecutors have filed a motion to add 10 new charges against accused Colorado gunman James Holmes, arrested following the July movie theater shootings that killed 12 people, and have asked to amend 17 others, the Denver Post reported on Wednesday.

The judge in the case has ordered nearly all court filings be sealed, and it was not clear what the additional charges were from a register of court actions, the Denver Post reported.

Holmes, a former neuroscience graduate student, is accused of opening fire on July 20 at a midnight screening of the Batman movie "The Dark Knight Rises" in Aurora, a Denver suburb. Twelve people were killed and 58 were wounded in the attack.

A court official declined to confirm the report of the additional charges.

Holmes, 24, already faces 24 counts of first-degree murder and 116 counts of attempted murder. Under Colorado law, the doubling of charges allows prosecutors to have two pathways to secure a conviction.

The newspaper noted that a separate motion was filed to amend 16 counts of attempted murder and one count of crime-of-violence sentence enhancement against Holmes, although it did not reveal how they would be amended.

Prosecutor Rich Orman said at a hearing last month that Holmes bought a ticket to the midnight screening, then left the theater through an exit door that propped open on his way out.

Holmes then put on a gas mask and ballistic protective gear before returning to the theater and spraying the crowd with gunfire, Orman said.

Wednesday's developments came a day before the scheduled continuation of a hearing on whether a parcel Holmes sent to University of Colorado psychiatrist Lynne Fenton falls under patient-doctor privilege.

Fenton testified at an earlier hearing that she treated Holmes more than a month before the rampage, but that their professional relationship had ended well before he mailed the package to her a day before the massacre.