Here's some grist for the mill ... BBC: Navy Yard: Swat team 'stood down' at mass shooting scene (Sept 18 2013) A tactical response team of the Capitol Police, a force that guards the US Capitol complex, was told to leave the scene by a supervisor instead of aiding municipal officers.The Capitol Police department has launched a review into the matter. Aaron Alexis, 34, killed 12 people at the Washington Navy Yard."I don't think it's a far stretch to say that some lives may have been saved if we were allowed to intervene," a Capitol Police source familiar with the incident told the BBC.The officers, wearing full tactical gear and armed with HK-416 assault weapons, arrived outside Building 197 a few minutes later, an official with knowledge of the incident told the BBC. According to a Capitol Police source, an officer with the Metropolitan Police Department (MPD), Washington DC's main municipal force, told the Capitol Cert officers they were the only police on the site equipped with long guns and requested their help stopping the gunman. When the Capitol Police team radioed their superiors, they were told by a watch commander to leave the scene, the BBC was told.