Barry Hollis, who pleaded guilty to sexually assaulting an 9-year-old girl during the summer, will be sentenced on Monday.
The incident happened on June 22, 2014 at Fantasy Island in the Town of Grand Island.
The assault happened on the "Crazy Mouse" roller coaster. Hollis, 36, was sitting next to the girl on the ride.
The girl's father, who did not share his name, spoke to 7 Eyewitness News and says that he hopes the sentencing of Hollis will bring his family some closure.
"We all want to put this behind us and start the healing process. For a while it was taking a back burner, but now that we're getting closer to 'D-day' as I'll call it, it's time to hopefully move on from it."
Hollis has also pleaded guilty to raping a 14-year-old girl, at Hamburg Beach. That incident happened in 2013, but the victim didn't come forward until August, 2014, when she saw Hollis' picture on the news.
He will learn his sentence for both charges on Monday.
Hollis faces a maximum of 14 years in prison.