Broward County isn't on the list. Must have been under surveillance by 'another agency'.
"The Bureau’s Public Corruption program focuses on:
-Investigating violations of federal law by public officials at the federal, state, and local levels of government;
-Addressing environmental crime, election fraud, and matters concerning the federal government procurement, contracts, and federally funded programs.
Election crimes become federal cases when:
-The ballot includes one or more federal candidates;
-The crime involves an election official abusing his duties;
-The crime pertains to fraudulent voter registration
-Voters are not U.S. citizens.
https://www.fbi.gov/investigate/public-corruption