The tactics used by police on Monday reflected a broader change in American policing in the years since the 1999 massacre at Columbine High School — as the words “active shooter” entered the national vocabulary.
Until that shooting in Colorado, the first responding officers would set up a perimeter and call in tactical officers, or members of SWAT. J. Pete Blair, director of research for the Advanced Law Enforcement Rapid Response Training, based at Texas State University, said that model proved fatal.
It can typically take at least 30 minutes for such teams to assemble and plan, Blair said, and at Columbine, “the shooter had free access to the school and could hunt down kids and kill them. There was a lot of public outcry and soul searching on behalf of the police.”
On Monday, police used more aggressive tactics, forming “active shooter teams” and going in quickly. The entire episode, from first shots to Alexis’s death, took between a half-hour and an hour, said Lanier, the D.C. police chief.
Police in Newport, R.I., said Tuesday that Alexis had called them last month from a hotel room there, complaining that he heard voices that followed him from hotel to hotel. Alexis also said that someone was using a “microwave machine” to sent vibrations through the ceiling, preventing him from sleeping, police said.
Alexis “stated that he has never felt anything like this and is worried that these individuals are going to harm him,” the report said. Police did not see a cause to arrest Alexis.
In Lorton, Va., a gun shop said that Alexis had purchased a Remington 870 shotgun and about two boxes of shells on Saturday, two days before the rampage. J. Michael Slocum, a lawyer for Sharpshooters Small Arms Range and gun shop in Lorton, said the shop ran a background check on Alexis through the federal database called the National Criminal Information Background Check System. Alexis was approved.
Alexis entered the Navy Yard with a valid pass, obtained through his work as a contractor, authorities said Tuesday afternoon. He was carrying a shotgun. Alexis may also have obtained a handgun during the rampage, authorities said.