An organization of federal workers, or agents, designed to secure the US against security risks that disrupt the government somehow
"clearing the picture" for other departments/agencies/forces or sending in their own forces for exigent purposes. They also have a nationwide web of phone/webtaps, informants, spies and undercover guys ("plants"). Founded in 1908 with the purpose of fighting crime more effectively nationwide, they eventually lasted through trying times such as the Prohibition, WW1
and continue their work today.
An agent: a suit with an signed ID. Usu. seen with a 9mm handguns, black Sedan and a red tie. *Some believe they are actually aliens.* ::GASP::