Three-letter Agencies

Three Letter Agencies are a general category of "spook" agencies, which defend America, but generally act mysteriously. A knock on the door at any hour from any of them should make you want to run for the back door or jump out the nearest window, except it won't help since they're already watching it. Some are likely to make you disappear. Some may just want to question you. Some, you'll never know about, but they're already watching you. It doesn't matter that you may not have heard of some of them, they already know who you are, who you've dated, and what you ate for breakfast. ATF - Bureau of Alcohol, Tobacco, Firearms and Explosives CIA - Central Intelligence Agency DEA - Drug Enforcement Agency DHS - Department of Homeland Security DIA - Defense Intelligence Agency DOD - Department of Defense DOE - Department of Energy (yes, them too) FBI - Federal Bureau of Investigation INR - Bureau of Intelligence and Research ISR - Air Force Intelligence, Surveillance and Reconnaissance Agency NRO - National Reconnaissance Office NGA - National Geospatial-Intelligence Agency NSA - National Security Agency ONI - Office of Naval Intelligence TFI - Office of Terrorism and Financial Intelligence USSS (United States Secret Service) falls into this category, even though it has 4 letter in its acronym.