FBI watched Spitzer before the incident that put him in hot water

From the Washington Post:

'Weeks before a hotel meeting with a prostitute that threatens to derail his career, the FBI staked out New York Gov. Eliot L. Spitzer at the same hotel in an unsuccessful effort to catch him with a high-priced call girl, according to a person with knowledge of the investigation. The FBI placed a surveillance team on Spitzer at the Mayflower Hotel for the first time on Jan. 26, after concluding from a wiretapped conversation that he might try to meet with a prostitute when he traveled to Washington to attend a black-tie dinner, the source said Tuesday.'