The Union County Sheriff's Office says remains that are believed to be those of a missing college student from Briar Cliff University in Sioux City have been found in the Missouri River.

Tom Patterson, 23, has been missing since Sept. 4. Patterson, of Frostburg, Maryland, was swimming with friends southwest of Elk Point when he disappeared.

Union County Sheriff Dan Limoges says new information from a witness indicates Patterson was trying to help other swimmers back to shore when he was swept away by the current.

The remains were sent to the Medical Examiner's Office in Sioux Falls for positive identification.