In Shooting's Wake, US Puts Security Under Microscope Plus: Aaron Alexis was barred from buying assault rifle By Matt Cantor, Newser User Posted Sep 18, 2013 3:24 AM CDT 17 comments Comments The American flags surrounding the Washington Monument fly at half-staff as ordered by President Barack Obama following the deadly shooting Monday at the Washington Navy Yard. (AP Photo/J. Scott Applewhite) (Newser) – As concerns grow over contractors' access to military bases, Washington is ordering at least three reviews of security practices. The White House is calling for a new look at "standards for contractors and employees across federal agencies," according to press secretary Jay Carney. Meanwhile, defense secretary Chuck Hagel has ordered a review of access to military bases worldwide, and navy secretary Ray Mabus is launching a "rapid review" of security of naval and marine bases, the Guardian reports. The reviews come as more details emerge from a Pentagon inspector general's report, via the Hill: Some 52 felons obtained access to installations for between 62 and 1,035 days. Hampered by a tight budget, the Navy came up short on background checks. More news on the attack and alleged attacker: Once the shooting began, the response was efficient, thanks to post-Columbine tactics to respond to "active shooters," the Washington Post reports. Police quickly formed teams and the situation ended with Aaron Alexis dead 30 minutes to an hour after the first shots. Though Alexis was able to buy a shotgun on Sunday, state law barred him from buying an AR-15 assault rifle he tried out, the New York Times reports. Out-of-state buyers can't purchase such weapons in Virginia, officials say.