Aledo, Ill. — The Mercer County treasurer was arrested Saturday on felony theft charges, and an auditor will investigate whether anything is awry in the county office.

Mike Bertelsen, 53, was taken into custody Saturday and was released after posting 10 percent of his $20,000 bond.

“Right now this involves a non-government allegation, but an auditor will be called in to audit the Mercer County Treasurer’s office,” Mercer County State’s Attorney Greg McHugh said.

Bertelsen has served as Mercer County Treasurer for five terms and last was re-elected in 2010. Bertelsen ran as a Republican for state senator of the 36th District in 2008 and lost to Democrat Mike Jacobs.

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A press release from the Aledo Police Department states the matter “is an ongoing investigation with Illinois State Police taking this investigation over with the Aledo Police Department and Mercer County Sheriff’s Department assisting.”

Bertelsen can continue to serve as treasurer because he has not been convicted of a crime, McHugh said.

In June, Bertelsen told county board members that county general fund expenses are exceeding revenues by about $45,000 per month. He and other Mercer County department provided budget reduction ideas at a special meeting of the Mercer County Board’s Finance Committee that included employee furloughs or days the courthouse would be closed.