In 1977, the Chicago Sun-Times purchased a bar and used it to uncover a system of corruption and bribery as health and fire inspectors demanded payments to overlook frayed wires, leaking pipes, rats, maggots and roaches.

Forty years later, former Sun-Times photographer Jim Frost will provide an insider’s look at the investigation, from 1-2 p.m., Saturday, March 31, in the Rocca Room.