Pupils must analyse five pieces of evidence to eliminate nine of ten suspects. Evidence covers all four NC Strands. Bearings, Angles, collecting like terms, ratios. Ideal as an end of term activity, pupils need to peform the common processes but also interpret their results in a different context. I usually have pupils working in pairs and run this over an hour session with ten minutes at the end to feedback their conclusions. Power point to support in delivery - with the answers on at the end. Suspects are celebrities, although the pupils love it if you put pictures of them or staff on!