FARMINGTON — A Shiprock man pleaded guilty in federal court on Wednesday to sexually assaulting a young in-law.

Herbert Ben Sr., 63, will be sentenced to two to five years in prison as a condition of his plea agreement, according to a news release from the U.S. Attorney's Office for the District of New Mexico. His sentencing hearing hasn't been scheduled. Ben Sr. will also be required to register as a sex offender.

Rosabelle Ben, 58, and Bruce Hamilton, 77, are also charged with sex crimes against the same girl. Rosabelle Ben allegedly forced the girl to perform sex acts on her husband, Ben Sr., and Hamilton in exchange for alcohol, according to court documents.

The victim told an FBI investigator that Ben Sr. assaulted her about 15 to 20 times and that Hamilton assaulted her about 20 times, according to court documents.

The assaults happened in Shiprock between August 2010 and December 2011 when the victim was 12 and 13 years old, according to the documents.

At the time of the assaults, the girl lived with several of her in-laws in Shiprock on the weekends.

She reported the assaults in April 2012, and all of the co-defendants were arrested the next month.

Rosabelle Ben and Hamilton have pleaded not guilty to the charges. Their trials are pending. The case was prosecuted as part of a U.S. Department of Justice initiative called Project Safe Childhood, which directs federal, state and local resources to better locate, apprehend and prosecute individuals who exploit children.

Ryan Boetel covers crime for The Daily Times. He can be reached at 505-564-4644 and rboetel@daily-times.com. Follow him on Twitter @rboetel on Twitter.