Police One Post

http://www.policeone.com/active-shooter/articles/1812419-Shoot-first-Columbine-transformed-police-tactics/

The Police One website is a for professionals website with news, articles, and reviews of a law enforcement nature.  In this particular article Banda addresses the Columbine High School Massacre of  1999 and effects of this tragedy on law enforcement tactics.  The key problem that occurred in Columbine is that arriving officers briefly engaged  the two shooters, but as soon as those shooters entered the building, the officers stopped engaging the suspects.  The officers then set up a perimeter waiting for the SWAT team to arrive as this was 30 years of policy pretty much nation wide.  Meanwhile both suspects continued their rampage until they killed themselves.  The key change that took place after Columbine is that officers are now trained to wait for back up (regardless of responding agency),  to make entry with those officers, locate the "active shooter," and engage them to prevent further loss of life and neutralize the shooter.