A northern Illinois firefighter was sentenced to 13 years in prison after pleading guilty to criminal sexual assault of a minor.

The Lake County News-Sun reports former Antioch firefighter Matthew D. Bielecki entered his guilty plea Friday in Lake County Circuit Court.

Assistant State's Attorney Jason Grindel says had the case against Bielecki gone to trial, testimony would have shown he had intercourse with a 15-year-old girl, with whom he held a position of trust as her modeling manager. He said the incident occurred between March 4 and Aug. 4, 2012.

Defense attorney David Weinstein said Bielecki could have been sentenced to 60 years in prison if convicted at trial of more than 20 felony charges.

Grindel said Bielecki must serve at least 85 percent of his sentence.

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