The horror and tragedy of mass shootings in American schools, churches and other public places capture the nation's attention. But analysis by @usatoday, @APNews and @Northeastern shows that these types of crimes, while terrifying, actually represent a small fraction of mass killings in America. Since 2006, there have been 504 mass killings that have taken the lives of 2,646 victims. Most incidents are committed by men with a handgun in a home, and most victims are people they know. James Alan Fox, a professor of criminology, law and public policy at Northeastern University in Boston, oversees the database and continues to add information drawn from media reports, FBI data, arrest records, medical examiners' reports, prison records, and other court documents. “A guy who kills his wife and children and sometimes kills himself is the most common type of mass killing,” Fox said. Tap the link in bio to explore the comprehensive database and analysis by USA TODAY, the Associated Press and Northeastern University.