In response to a Freedom of Information Act request, the FBI has just released for the first time hundreds of memos regarding its "special file room," in which it has stored for decades information considered too sensitive for its central filing system. As described by the Boston Globe, the special filing system is designed "to restrict access [to information] severely and, in more sinister instances, some experts assert, prevent the Congress and the public from getting their hands on it." The information includes such things as plans to relocate Congress if Washington is attacked, files on high-profile mob figures and their political friends, as well as the FBI's own questionable activities such as spying on domestic political organizations. From the Globe:
Other files on domestic spying that were routed to the special file room involved "black nationalist extremists." There were also files about an "extremely sensitive counterintelligence technique" called snitch-jacketing, which apparently involved the FBI spreading false information that members of a targeted group were government informants in order to sow conflict within their membership.
While "snitch-jacketing" was a new term to me, it's an old concept. An important historical strand of informant use has been the government's creation and deployment of informants to infiltrate and disrupt civilian political activities. I've blogged about this issue here in the context of FBI infiltration of Muslim communities; Gary Marx is the preeminent expert on this subject.