Unconfirmed reports say the men are friends of the suspects.
Witnesses said at least two gunmen in black trench coats and masks opened fire and tossed an explosive device Tuesday at the high school southwest of Denver. At least 18 people have been taken to hospitals with gunshot wounds, local television reported. One female student was shot nine times in the chest, another female student was shot once in the chest and a male student was shot once in the back. There was no confirmation that the gunmen were still inside, but police said some students had been hiding in a choir room. SWAT team members are among the 100 to 200 law enforcement officers at the scene.