James Holmes, the suspect in the tragic movie theater massacre in Aurora, Colorado, will be in court for a key preliminary hearing today. The 25-year-old is charged with killing 12 people and wounding dozens more. Prosecutors will begin presenting evidence and are expected to call scores of witnesses before Arapahoe County District Judge William Sylvester. He’ll determine whether the evidence is sufficient for Holmes to stand trial on more than 150 counts, including murder, attempted murder and weapons charges. The weapons included explosives allegedly used to booby-trap Holmes's apartment.
Holmes’s attorneys are expected to present a diminished mental capacity defense in the preliminary hearing that is expected to last several days. Up until now, the judge had ordered a sweeping gag order, so this will be first time the public will hear details of what went on inside the theater during the shooting rampage back in July. CNN's Casey Wian is live in Centennial, Colorado this morning with more.