Most government agencies are rather secretive when it comes to the information they share with other agencies and with the public. The best document to read regarding this would be here: http://nsi.ncirc.gov/%28S%28kdyhncjxg2gklzboxcosmno4%29%29/documents/National_Strategy_for_Information_Sharing.pdf?AspxAutoDetectCookieSupport=1 It's the National Strategy for Information Sharing, and is specifically about information sharing as it relates to terrorism. The US Government Accountability Office also has this information, which is more recent: http://www.gao.gov/products/GAO-13-471