The 1999 killings at Columbine dramatically changed how U.S. law enforcement responds to "active shooter" attacks, Washington, D.C., police chief Cathy Lanier tells Anderson Cooper
The 1999 killings at Columbine dramatically changed how U.S. law enforcement responds to "active shooter" attacks, Washington, D.C., police chief Cathy Lanier tells Anderson Cooper. Based on early information, a law enforcement source questions whether Paris police moved quickly enough into the Bataclan concert hall.
