ABERDEEN, S.D. — A 51-year-old Mandan, N.D., man has been sentenced to 30 years in prison for aggravated sex abuse and incest with a child under the age of 12.

Ronnie White Mountain was sent to prison this week in federal court in Aberdeen from an incident almost a decade ago when he was visiting relatives in McLaughlin, S.D., just across the North Dakota border on the Standing Rock Indian Reservation.

Following a night of drinking, White Mountain returned to a family member's home and engaged in a sex act with the child, said the charges. The incident occurred between January 2010 and December 2012, said the court.

The FBI investigated the case.