Robert O’Brien, a detective assigned to the 28th Security Forces Squadron, dusts for fingerprints on a knife at Ellsworth Air Force Base, S.D., Nov. 10, 2016. The unique pattern of individual human prints was discovered during the 19th century by Henry Faulds while working as a medical missionary in Japan and is critical to identifying persons when conducting investigations. (U.S. Air Force photo by Airman 1st Class Donald C. Knechtel)