The FBI reportedly collected evidence from the Illinois Capitol and the district offices of a Democratic state senator Tuesday.
Media reports said the raid was completed at state Sen. Martin Sandoval's Capitol and Cicero, Ill., district offices, in addition to other affiliated locations.
Bureau agents were seen carrying bankers' boxes and grocery bags, with at least one marked as "evidence," out of the Illinois Statehouse in Springfield, The Associated Press reported.
A desktop computer wrapped in plastic was also removed from the premises and taken into two SUVs along with the other collected materials, the Chicago Tribune reported.
FBI spokesman John Althen told the AP the agents were there for "law enforcement activity" but did not provide additional details. The Hill has reached out to the FBI for comment.
Sandoval, 55, has been a senator for Chicago's southwest side since 2003 and heads the Transportation Committee, according to the Tribune.
Multiple political scandals have disrupted Illinois politics this year. Chicago Alderman Edward Burke was indicted on corruption charges in June, according to the Tribune. And in August, state Sen. Thomas E. Cullerton pleaded not guilty to allegations that he did little or no work and took salary and benefits from the Teamsters Union.