Joel Greenberg, the former Florida tax official at the center of an investigation into representative Matt Gaetz, has been providing information on the lawmaker's activities to investigators since last year.
Unnamed sources told The New York Times Greenberg gave information on how he and Gaetz paid women for sex using cash or gifts, which potentially violates federal trafficking laws.
Investigators are also looking into allegations that Gaetz had sex with an underage girl. Gaetz has repeatedly denied all allegations and has not been charged with any crime.
Greenberg, meanwhile, faces 33 federal charges including bribery, identify theft and sex trafficking of a minor. His lawyer says he will likely plead guilty.