The McHenry County Sheriff's Office said Nicholas S. Kachiroubas, 45, of Crystal Lake was arrested.
He was being investigated by the National Center of Missing and Exploited Children.
He's accused of grooming children and possessing child pornography.
SEE ALSO: Good Samaritans pounce on child rape suspect, tie his legs and detain him for New York police
The sheriff's office said they executed a search warrant in the 200-block of South Dole Avenue Tuesday, which led to Kachiroubas' arrest.
ABC7 Chicago news partner the Daily Herald reported that Kachiroubas is the city clerk for Crystal Lake.
He also sits on the Illinois Community College Board, and is an associate professor for DePaul University.
He's expected in court Thursday.