Mason City police say they were called to a home after the dog attacked its owner, 19-year-old Dallas Lewis, as well as another occupant of the residence, 50-year-old Kyde Ratliff.
Police say the two men tried to stab the dog with a knife to stop the attack.
Police later captured the dog with catch poles, but the dog later died. Police say the dog had bitten someone in September, but the bite was not severe enough to declare the dog as a vicious animal.
Lewis and Ratliff were listed last night in fair condition at Mercy Medical Center-North Iowa after suffering numerous bites.
By Bob Fisher, KRIB, Mason City