DETROIT LAKES, Minn. — An 18-year-old woman has been sentenced in Becker County District Court on a felony charge of first-degree criminal sexual conduct.

Monika Jeanmarie DeMarrias, of Yankton, S.D., was found guilty by a jury in October of sexually assaulting three children under the age of 8 multiple times from Jan. 1 to Aug. 5, according to court records.

The assaults occurred in a residence in Becker County, Minn., and the oldest victim said she was afraid to tell sooner because Demarrias frightened her with a knife and threatened to kill her and her family if she told anyone, according to the juvenile court complaint.

The oldest victim said she witnessed some of the assaults on the younger two victims. The victims often were tied up and gagged during the sexual assaults. Physical assaults included choking, beating and holding the younger ones out a high window by their legs as if planning to drop them, according to court records.

Demarrias was charged under Extended Juvenile Jurisdiction and on Nov. 5, District Judge Gretchen Thilmony sentenced her under that jurisdiction to 144 months — 12 years in prison, execution of sentence stayed.

Newsletter signup for email alerts

Thilmony ordered her to get individual trauma therapy and counseling with Lutheran Social Services and follow all mental health recommendations.

DeMarrias must complete the Massachusetts Youth Screening Instrument, and attend any medication management appointments deemed appropriate. She must get a chemical dependency evaluation and follow the recommendations, abstain from alcohol and illegal drugs, and have no contact with the victims, nor any unsupervised contact with children under age 16.

She must complete juvenile sexual offender treatment and do 50 hours of community service work. She was placed on probation for an indeterminate amount of time and must remain in a secure juvenile facility for an indeterminate amount of time.

No sentence was pronounced on a second felony charge of first-degree criminal sexual conduct, and felony charges of second-degree assault and terrorist threats were dismissed.