Well while I am unable to disclose which agency I work for, I can assure you there is "watchers over the watchers" but this isn't that Will Smith movie, it's a tad more complicated than that. As for the invasion of privacy, unless you fit the demographic of persons of interest, you have nothing to worry about, it's more of a select few.
The document that was from was the Patriot Act, Rev. 9th Mar, 2007.
XI Wiki

