Technologies to Detect Concealed Weapons: Fourth Amendment Limits on a New Public Health and Law Enforcement Tool

Firearm violence is a major public health problem in the United States. In 2000, firearms were used in 10,801 homicides – two-thirds of all homicides in the U.S. – and 533,470 non-fatal criminal victimizations including rapes, robberies, and assaults. The social costs of gun violence in the United States are also staggering, and have been estimated to be on the order of $100 billion per year.Illegal gun carrying, usually concealed, in public places is an important risk factor for firearm-related crime. In the 1980s and 1990s, police departments across the country began to develop and implement strategies to address illegal weapons carrying. Often these strategies have involved aggressive efforts to identify and physically search individuals suspected of illegally carrying a firearm.