On Sept. 24, 2005, tens of thousands of protesters marched past the White House Unknown to the crowd, biological-weapons sensors, scattered for miles across Washington by the DHS six of those machines sucked in trace amounts of deadly bacteria called Francisella tularensis.biological weapons most likely to be used against the US http://dir.salon.com/story/news/feature/2005/10/18/tularemia/index.html