Colorado movie massacre gunman James Holmes was found guilty on Thursday of multiple counts of first degree murder and attempted murder, a verdict that enables prosecutors to seek the death penalty for the former graduate student who killed a dozen people and wounded 70 at a midnight premiere of a Batman film in 2012.

After a three-month trial in which they were presented with thousands of pieces of evidence and testimony from hundreds of witnesses, jurors deliberated for about a day and a half, then handed prosecutors a big win. The panel of nine women and three men rejected the defense's claim that Holmes was legally insane.

Holmes showed no reaction as the lengthy, multicount verdict was read by Arapahoe County District Court Judge Carlos Samour. The gunman stood beside his court-appointed attorneys, looking straight ahead with his hands in his pockets.