Active-shooter training evolves from lessons learned at Columbine
04/20/2016 11:26 am PDT
The April 20, 1999 attacks at Columbine High School in Littleton, Colorado changed the way law enforcement responds to school shootings.
The April 20, 1999 attacks at Columbine High School in Littleton, Colorado changed the way law enforcement responds to school shootings.
