Rodney Berget and Eric Robert are both convicted kidnappers. Berget is serving a life sentence and Robert is serving 80 years.
During a morning escape attempt, the pair assaulted two guards. One guard was pronounced dead in a hospital. The other guard sustained minor injuries.
Further escape details were not released.
Berget and Robert were apprehended on the grounds of the South Dakota Penitentiary.
The Associated Press contributed to this report.