Did the shooting happen around the campus of the University of Colorado? If yes, aren’t most universities gun free zones? That’s where most of the massacres have occurred. Criminals are no fools. They don’t want to try a killing spree in a place when someone might be armed and give them what they deserve.
The commonly known University of Colorado main campus is at Boulder, NW of Denver. I have read that this place, east or south of Denver is called University of Colorado-Denver, or University of Colorado Medical school.
I’m a Kansan, and don’t know much about this. May be a situation like the University of Kansas (Lawrence), with it’s medical school located in Kansas City, KS, with branches in one or more different locations.