James Holmes is accused of spraying gunfire at a theater full of people during a midnight screening of The Dark Knight Rises last summer, murdering 12 and wounding 59 others.
Today, a Colorado judge denied his attorney's request for more time to build an insanity defense and entered a standard not guilty plea on the 25-year-old's behalf.
"As far as we're concerned, they are entering a plea of not guilty, and what they have done to this point is not sufficient to enter a plea of not guilty by reason of insanity," Karen Pearson, an assistant district attorney for Arapahoe County, said in court.
Prosecutors said they would announce whether or not they plan to seek the death penalty against Holmes at a hearing scheduled for April 1.
The onetime University of Colorado Ph.D. candidate is charged with 24 counts of first-degree murder (double the victim count due to special circumstances), 116 counts of attempted murder, possession of explosive devices and inciting violence.
Judge William P. Sylvester said in court that Holmes might be given truth serum or forced to take a lie-detector test to determine his state of mind during the shooting.