The public gets its first look Monday at what police say really happened six months ago when a gunman shot dozens of people inside a Colorado movie theater.

The evidence against James Holmes has been sealed until Monday. 

The shooting happened during a midnight screening of the most recent Batman movie "The Dark Knight Rises." A source says Holmes told police he dyed his hair red before the rampage because he was "the Joker," one of Batman's arch nemesis.

Monday's hearing could be the start of several days of possibly disturbing testimony which will help the judge decide if Holmes will stand trial.

Holmes has not entered a plea, but his attorneys are expected to say he did not know what he was doing.

Read more: Tragedy in Colorado