In the weeks since FBI and IRS agents raided the home, Cicero and Springfield offices of State Sen. Marty Sandoval (D-Chicago) and swiftly turned their attention to the village halls of McCook and Lyons, it has become clear that a sprawling corruption investigation is underway — one that has the power to reshape Illinois politics.

But as the raids multiply — and more politicians are targeted — it has become a challenge with keeping all the players and the issues straight. This encyclopedia will be updated developments occur. 

Federal agents are examining at least seven towns — as indicated by the existence of “Municipality 7” mentioned in the search warrant for Sandoval’s Springfield office, which instructed agents to collect documents related to its president and attorney.