A witness to the Saturday morning shootings in Colorado Springs called 911 before the man fired at the victims. According to a
Denver Post article
she told reporters
she recognized the gunman as her neighbor — whom she didn't know by name — and that before the initial slaying she saw him roaming outside with a rifle. She called 911 to report the man, but a dispatcher explained that Colorado has an open carry law that allows public handling of firearms.
She also observed that "He did have a distraught look on his face".
I wonder if the police were actually prevented from responding to the call before the shootings happened because of this law. Or maybe it was simply mentioned while officers were being dispatched as a precaution. I suppose we'll know when investigators finally explain what happened.