Definition: In this task, you need to generate an appropriate title for the given summary of some paragraph. The generated title must be short and should include the main topic of the given text. Your summary should be less than 20 words long.
Input: A police officer was killed in a "ferocious attack without mercy" when he was set upon by an armed mob during rioting in north London in 1985, a court has heard.

PC Keith Blakelock: Murder trial told armed mob killed officer