One of the first things you will have to do is decide on a crime. Ideally it will be a crime that could take place in your school or community and could involve staff members. Determine what evidence would be left at the scene of the crime. Consider using handwriting, hair, clothing, fingerprints, footprints, or simulated blood. Choose things that could actually be left at a crime scene and that would be unique to each suspect. Write a newspaper article or press release that will introduce students and faculty volunteers to the crime. Remember that all of this evidence is circumstantial. Students will have to tie in witness testimonies, establish a motive, and build a strong case to prove the person guilty.