The Webster Police chief said the two killed firefighters, including a volunteer officer who was also a police lieutenant, did not expect to be "shot and killed" in the line of duty.
More top news
Princess Eugenie has become engaged to long-term boyfriend Jack Brooksbank, Buckingham Palace has announced.
Young women are not attending smear tests because they are embarrassed about their pubic area, a cancer charity has warned.
Amazon is opening its first artificial intelligence-powered supermarket in Seattle on Monday.