For your perusal: The New FBI Operations Manual. "Agents may begin such assessments against a target without a particular factual justification. The basis for such an inquiry “cannot be arbitrary or groundless speculation,” the manual says, but the standard is “difficult to define.”
Since at least February, the St, Paul police and the FBI have been trying to infiltrate protest groups planning to demonstrate and the RNC. Apparently they were successful because they have begun arresting protestors before the convention actually starts. They even went after the press. I have to wonder if any MeFites were busted?