"That officer is in a very, very tough place; unimaginable what that officer has to be feeling right now," Chicago Police Supt. Larry Snelling said.

Chicago police officials say an officer killed this week was accidentally shot and killed by her partner after they encountered someone with a rifle when they chased a suspect into an apartment.

Chicago Police Supt. Larry Snelling on Saturday cautioned against a rush to judgment, after police confirmed Officer Krystal Rivera was accidentally shot and killed by a fellow officer Thursday night during a chase in the Chatham neighborhood.