HAMMOND, Ind. (AP) — A federal prosecutor says a retired police officer was instrumental in an investigation that led to bribery charges against a northwestern Indiana sheriff, his top deputy and a mayor.

U.S. Attorney David Capp says Scott Jurgenson’s voluntary cooperation and assistance helped federal investigators uncover the alleged corruption.

The (Northwest Indiana) Times reports that Jurgenson served 22 years as an officer with the Merrillville Police Department. He’s now owner of Samson’s Towing of Merrillville.

The indictments announced Nov. 18 name Lake County Sheriff John Buncich, Chief Deputy Tim Downs and Portage Mayor James Snyder. They allegedly collected bribes in return for contracts for towing and other services.

Tow company owners William Szarmach and John Cortina were also indicted. They are accused of making payments in exchange for contracts.