A 64-year-old Austin man accused of molesting an underage girl over the last eight years was sentenced Thursday to seven and a half years in prison.

Michael Carl Koch was convicted of second-degree criminal sexual conduct with a victim younger than 16 and fourth-degree criminal sexual conduct with a victim 16 to 17. Both charges are felonies. Three other felony criminal sexual charges were dismissed.

According to a court complaint, Koch began sexually abusing the victim, a 16-year-old girl, when she was about 8. Austin police learned of the alleged abuse from Mower County Human Services.

The girl told police Koch has touched her inappropriately and engaged in sexual activity with her on several occasions without her consent. The most recent incident happened on May 4, 2011, when Koch bought the girl a swimsuit and had her try it on for him. When he asked if he could take photos of her wearing it, she refused.

Koch took nude photos of the girl between the ages of 11 and 14, the girl told police.

When authorities interviewed Koch, he admitted to buying the swimsuit and asking for pictures of her in it. However, he denied ever touching her, saying he walked in on her in the shower once but left the bathroom immediately. Koch told police he tells the girl she has nice breasts and that she is pretty, according to a court complaint.

—Amanda Lillie contributed to these reports.