Avon and Somerset Police Antony Snook will serve a minimum of 38 years in prison A man who drove four teenagers on a revenge mission that led to two best friends being murdered has been handed two life sentences. Mason Rist, 15, and Max Dixon, 16, died after being stabbed by four teenagers in a frenzied attack outside Mason’s home on Ilminster Avenue in Knowle West, Bristol, on 27 January.