CATCHING A TERRORIST
The FBI also had decided it was time for more extreme measures - as [FBI agent] Frank Watts put it, it was "time to fight fire with fire." Even though he had no hard evidence, he was convinced that Tarrants had bombed the synagogue, and he felt the quickest way to nail Tarrants would be to lay a trap for him. To do that would involve the unpleasant chore of recruiting the Roberts brothers as informants, but Watts figured, "You just have to deal with the scum of the earth to catch the scum of the earth."
... "Once the Jews were attacked," Watts said, "it was a different ball game. ... It involved the whole United States." People were putting pressure on senators and congressmen and demanding that action be taken against the terrorists. Hoover decreed that every morning, seven days a week, Watts was to file a Teletype to Washington keeping the director abreast of every development.