Central Oregon authorities say a 79-year-old man took a 1930 Ford Model A coupe to church on Sunday to show it off.
But when he left it so he could get a bite of lunch, sheriff's deputies say, it was stolen and crashed into the Crooked River south of Prineville.
Photos show the mangled vehicle in the river, but no estimate of the damage was immediately available.
KTVZ-TV reports that the man was fixing the car for a family that owned it.
Capt. Michael Boyd says 34-year-old Erik Blake Halpin, described as a transient, was accused of drunken driving and unauthorized use of a vehicle. He swam to shore and was arrested after he was treated at a Bend hospital.