The memo said agents discussed “past and upcoming meetings” of the movement, and its spread. It said agents should contact Occupy Wall Street activists to ascertain whether people who attended their events had “violent tendencies.”

The memo said that because of high rates of unemployment, “the movement was spreading throughout Florida and there were several Facebook pages dedicated to specific chapters based on geographical areas.”

The F.B.I. was concerned that the movement would provide “an outlet for a lone offender exploiting the movement for reasons associated with general government dissatisfaction.”

The records provide one of the first glimpses into how deeply involved federal law-enforcement authorities were in monitoring the activities of the movement, which is sometimes described in extreme terms.