An Oconto County man will serve five years in prison and 15 years on extended supervision for sexually assaulting a mentally disabled Kewaunee County girl.

Danial L. Thiry, 50, Abrams, was sentenced Monday by Judge D. Todd Ehlers in Door County Circuit Court for two counts of second degree sexual assault of a mentally ill victim on July 3 and Oct. 28, 2003.

According to the criminal complaint, Thiry, who owned a metal siding and roofing business, Mecca Construction in Abrams, hired the girl through her adoptive parents in Kewaunee County in 2001. The assaults that continued over the next eight years spanned job sites in Door, Kewaunee, Brown and Oconto counties.

Authorities pieced together the dates of the assaults after the brain injured woman said she no longer wanted to work for Thiry last June. The girl, now 24, has an understanding level equivalent to about sixth grade. Her adoptive parents allowed her to work for Thiry at job sites as part of a cleanup crew until she explained why she no longer wanted to work for the man. Thiry claimed he knew the girl was "slow" but thought she was 20 years old at the time.

Four other felony charges of second-degree sexual assault with use of force and sexual assault from 2003 and 2004 were dismissed but read in to the record. Thiry was ordered to have no contact with the victim, her residences, her adoptive parents, her employment or contact with any vulnerable adults or juvenile females. He must undergo sex offender treatment and register on the state sex offender registry.