Section 31
From FEInfobase
Section 31 is allegedly an officially nonexistent and uncondoned rogue agency within Starfleet Intelligence that claims to operate in the name of the security of the United Federation of Planets. Little information is available about the activities of the organization, though one of its operatives is purported to have claimed that Section 31 deals with threats to the Federation that others do not even realize exist. Section 31's actions are said to be autonomous and not controlled by Starfleet Command or the Federation government. The supposed activites of this group range from loyalty tests to advanced R&D to political manipulation and corruption to black ops and beyond. Some of the more fantastic, and quite certainly false, allegations include lurid tales of entire fleets crewed by ruthless killers.
There has never been any public or internal statement made by the Federation government on the topic, and the name Section 31 is generally unknown to civilians. Even among Starfleet officers in the latter part of the 2370's, stories of Section 31's exsistance were comperable a to little-known and even less-beleved urban ledgend. Some officers, notably Admiral Falco Tauvits, took every oppertunity to berate and belittle anyone expressing a belief in the veracity of rumors about Section 31, calling such tales paranoid fantasies. Still, the story persists as occasional whispered conversations over late night drinks in officer bars all across Earth.