The key to solving gun crimes may lie in the casings. That’s why a U.S. attorney, the Appalachian High-Intensity Drug Trafficking Area and the Bureau of Alcohol, Tobacco, Firearms, and Explosives are asking West Virginia law enforcement to bring casings from crime scenes to a gun crime mobile unit so they can expand their database. Gun shell casings can be as unique as a fingerprint since only one gun produces the same imprint every time. Eyewitness News reported that thel agencies are taking technology on the road to expand the database and potentially catch more criminals.