Mass shootings in populated places have risen steadily in the U.S. from 2000 to 2013, said a 2014 FBI study reported by the Boston Globe. These incidents happened an average of 11.4 times a year — or slightly less than once per month — between 2000 and 2013. Active shooter incidents are defined by the U.S. government as “an individual actively engaged in killing or attempting to kill people in a confined and populated area,” like a mall, school, or church. Between 2000 and 2013, 486 people died and 557 were wounded during 160 active shooter incidents, according to the FBI. Most involved a solo male shooter.
In most incidents, the violence ended before police arrived, when the shooter died by suicide (which happened 40 percent of the time), stopped shooting, or fled the scene. In 21 cases, the shooter exchanged fire with law enforcement. Nine officers died while engaging active shooters. Five shooters from four incidents remain at large. About 40 percent of active shooter incidents are mass killings, when three or more people are killed. The FBI study did not look at other types of mass killing cases, nor did researchers look at incidents involving domestic violence, gang or drug violence, hostage situations, self-defense conflicts, or deadly crossfire as a byproduct of another ongoing criminal act.