Boldly rejecting a plea deal in a case of mass killing and setting up a showdown on mental health, prosecutors announced Monday they will seek the death penalty against James Holmes for killing 12 people in a movie theater last summer in Aurora, Colorado.

The Denver Post reports the prosecution claimed to consult 800 survivors, victims' relatives, and more before ultimately coming to the conclusion to pursue the death penalty against Holmes. "It is my determination and my intention that in this case, for James Eagan Holmes, justice is death," District Attorney George Brauchler said in court Monday. Holmes shot and killed 12 people and injured at least 58 others during a midnight screening of The Dark Night Rises on July 20, 2012. 

Last week, Holmes's attorneys tried to end what will surely be a long and emotional trial early with an offer for their client to plead guilty to all 166 charges of murder and attempted murder in exchange for a life sentence without a chance of parole. The aim was to avoid dragging a trial out any longer and for Holmes to avoid facing the death penalty. The prosecution flat-out rejected that offer late in the week, accusing the defense of trying to drum up public sympathy. But there remained questions of whether prosecutors would still seek the death penalty — because Colorado does not have much of a recent history in invoking it, and because the burden of proving Holmes was not insane will lie with the prosecution.

Indeed, the Holmes trial will now move forward with a start date scheduled for August 5, though Holmes's attorneys are expected to request a delay. They are expected to mount an insanity defense, which is much easier to do in Colorado. As we've explained, in most states the burden of proving insanity falls on the defense. But in Colorado it's the prosecutors' job. They have to prove he is not insane, instead of the defense proving he is insane, which is how most states operate. While there is little doubt that Holmes was the shooter — a guilty plea offer is a tacit admission, after all — those 800 interviews will have to amount to something like a burden of proof. But expect to hear from many psychological experts regarding the insanity of Holmes as two of the most dramatic issues in America right now — mental health and gun violence — collide in a high profile summer trial.