Brihard said:
But no, it's not usually 'all over' by the time police go in.
About 60% of the incidents in the US are over by the time the police get there, based on the 2013 study of active shooters between 2000 and 2013. Not sure what that equates to when you roll in data from 2013 until now. When I do Active Shooter presentations for varying entities, I draw a lot of my statistics from this report. I do note the date of the report when I cite statistics however. Also note that this report isn't specific to school shootings only.
http://www.firestorm.com/wp-content/uploads/2014/10/k2_attachments_U-_ActiveShooter13B_WEB.pdf
INCIDENTS
■ An average of 11.4 incidents occurred annually.
■ An average of 6.4 incidents occurred in the first 7 years studied, and an average of 16.4
occurred in the last 7 years.
■ 70.0% of the incidents occurred in either a commerce/business or educational
environment.
■ Shootings occurred in 40 of 50 states and the District of Columbia.
■ 60.0% of the incidents ended before police arrived
CASUALTIES
■ Casualties (victims killed and wounded) totaled 1,043. The individual shooters are not
included in this total.
■ A total of 486 individuals were killed.
■ A total of 557 individuals were wounded.
■ In 64 incidents (40.0%), the crime would have fallen within the federal definition of
“mass killing”—defined as “three or more” killed—under the new federal statute.
INCIDENTS WITH THE HIGHEST CASUALTY COUNTS:
■ Cinemark Century 16 Theater in Aurora, Colorado:
70 (12 killed, 58 wounded), July 20, 2012.
■ Virginia Polytechnic Institute and State University in Blacksburg, Virginia:
49 (32 killed, 17 wounded), April 16, 2007.
■ Ft. Hood Soldier Readiness Processing Center in Ft. Hood, Texas:
45 (13 killed, 32 wounded), November 5, 2009.
■ Sandy Hook Elementary School and a residence in Newtown, Connecticut:
29 (27 killed, 2 wounded), December 14, 2012.
SHOOTERS
■ All but 2 incidents involved a single shooter.
■ In at least 9 incidents, the shooter first shot and killed a family member(s) in a
residence before moving to a more public location to continue shooting.
■ In at least 6 incidents, the shooters were female.
■ In 64 incidents (40.0%), the shooters committed suicide; 54 shooters did so at the scene
of the crime.
■ At least 5 shooters from 4 incidents remain at large.