An Arvada, CO, police officer was killed Monday afternoon while responding to a shooting in Olde Town Arvada that forced people to flee and others to hunker down in their shops.

Arvada police Detective David Snelling said shots were fired in the area Monday afternoon that two possible suspects were “down.” He wouldn’t say whether they were injured or killed. Arvada police have not released more details about the incident, the Denver Post.

Arvada police first reported the incident via Twitter at 1:53 p.m. Monday. Dozens of police officers from several Denver-area agencies responded to the area Monday afternoon.