MOORHEAD, MN (KFGO) – Moorhead police say 14-year-old Jaelyn Walker of Moorhead was the victim of a homicide early Tuesday morning.

Walker was reported missing Monday evening and her body was found near the river in the area of Elm Street and 6th Avenue S.

Isaac Arndt, 18 of Fargo, was arrested for her murder Tuesday. Police say Walker and Arndt knew each other.

Walker’s body was sent to the Ramsey County Medical Examiner’s Office in St. Paul for an autopsy. Capt. Deric Swenson says police will not be releasing Walker’s cause of death until those results come back.

Investigators are asking for the public’s help in finding a Samsung Galaxy phone in an orange phone case believed to be near where Walker’s body was found and the 1700 block of 5th Avenue S. in Fargo. They would also like to speak with anyone who gave Arndt a ride Monday evening.

Anyone with information should call Red River Regional Dispatch.