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Police investigate a scene after a St. Louis police officer was shot in what the police chief called an "ambush" on Sunday, Nov. 20, 2016, in St. Louis. Police Chief Sam Dotson said the 46-year-old officer was shot in the face. The suspect got away and a massive search was underway. (David Carson/St. Louis Post-Dispatch via AP)
Police investigate a scene after a St. Louis police officer was shot in what the police chief called an "ambush" on Sunday, Nov. 20, 2016, in St. Louis. Police Chief Sam Dotson said the 46-year-old officer was shot in the face. The suspect got away and a massive search was underway. (David Carson/St. Louis Post-Dispatch via AP)

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Four officers shot in targeted attacks

Four police officers were killed in separate targeted attacks across the country. CNN's Polo Sandoval reports.

Four officers shot in targeted attacks

Four police officers were killed in separate targeted attacks across the country. CNN's Polo Sandoval reports.