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: The mother and twin sister of a 15-year-old boy who was killed in a gun and knife attack have taken part in a vigil to mark one week since his death.

Keon Lincoln: Vigil marks week since schoolboy's killing