Special Agent Tam Reed carefully pours a dental solution into a mock footprint to get a three-dimensional impression of the shoe sole. The technique, called casting, results in a hardened mold in about 45 minutes. It can also be used to take car tire impressions as well as two-dimensional impressions, such as footprints on slick floor surfaces or fingerprints on window sills. Agent Reed is a forensic science consultant with the Air Force Office of Special Investigations' 33rd Field Investigations Squadron. (U.S. Air Force photo/Bobby Jones)