Building a powerful case against a criminal requires effective processing of the crime scene. Evidence missed there is gone forever. Setting up a mock crime scene teaches law enforcement students the processes and roles in crime scene investigations and helps them understand the application of general scientific study, such as how hypotheses should be constructed. Set up your scene by establishing your scenario and location; then create appropriate evidence and paperwork.

Work Backward and Set Tasks

First establish clear goals for the activity so you can measure the outcome. If you want to emphasize fingerprinting, for instance, you need to create a scene with multiple fingerprints or prints in places where the prints are difficult to extract, such as on fabric. Decide who the perpetrator is and what clues will lead students to that conclusion so they have a trail to follow. Determine the types of evidence each student or team is in charge of to create more orderly collection. One person or group might pick up DNA samples, another look for fingerprints and a third take photos with one as lead investigator, for example. Choose a scenario and evidence so each person or group will have material to find.

Select Your Location

Choose a location for the scene that allows for appropriate recovery of clues. Areas with lots of foot traffic create confusion and distractions for students who are investigating the scene. Potential contamination exists in such areas, as well, so public places might make good sites for more experienced students. Outdoor locations may also be more difficult to manage. For beginners, your classroom or any other private or semiprivate area creates a more controllable scene. If the activity will span more than one class period or day, consider how well the scene can be protected overnight.

Place Evidence

Use clothes stuffed with material or a mannequin for a body and washable paint for blood. Collect and place other evidence in the scene, such as hair and fibers from your body, your home and your volunteers. Use volunteers to place fingerprints if feasible; otherwise, present a report with fingerprint evidence. Cigarette stubs, gum and empty coffee cups yield DNA. If you want students to use witnesses as well, find people willing to be interviewed or type up "reports" giving pertinent information.

Provide Forms and Guidelines

Students will need access to appropriate tools and information before examining the scene. To document before investigating, students need cameras. Create or purchase crime scene tape, latex gloves and evidence markers and bags. Tape measures help students establish specific locations and make accurate drawings of the scene. For students just learning about crime scene procedures and forensics, you might need to create a checklist explaining the procedures, such as taking pictures before disturbing the scene and labeling compass directions on a sketch of the scene.