"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.

Adrian Rucker is charged with confronting police while armed with a rifle, which led an officer to open fire and fatally shoot Officer Krystal Rivera Thursday in Chatham.

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.