ELK POINT, S.D. -

South Dakota authorities have confirmed that a body recovered from the Missouri River was that of a missing Iowa college student.

The Union County Sheriff's Office said Thursday that the medical examiner's office in Sioux Falls says the body was that of 23-year-old Tom Patterson. He disappeared in the water around 5 p.m. Sept. 4 near a beach about four miles southwest of Elk Point.

Authorities have said witnesses reported that Patterson was trying to help some companions swim from the Nebraska shoreline back to South Dakota when he was swept away by the current.

Patterson was from Frostburg, Maryland, and was a student at Briar Cliff University in Sioux City, Iowa.