The suspect in a U.S. movie theater massacre has been charged with multiple counts of first degree murder and attempted murder, for the shooting attack in which 12 people were killed and 58 were wounded.

Prosecutors filed formal charges Monday against suspect James Holmes in Colorado. They say they will decide whether to seek the death penalty in the coming weeks.

Authorities say Holmes went on a shooting rampage in the city of Aurora July 20. The attack took place during the midnight screening of the new Batman film, The Dark Knight Rises. Police say Holmes threw a tear gas bomb in the theater before opening fire on the audience.

Reporters at the courthouse Monday say Holmes appeared just as unemotional as he did in his first court appearance a week ago.

Holmes, a former Ph.D. student in neuroscience, has refused to talk to police.

In all, prosecutors filed 142 charges against Holmes, including counts of murder with extreme indifference, attempted murder and possession of explosives.

After Holmes' arrest outside the movie theater, police said they found his apartment booby trapped with explosive devices.