HONOLULU -- Three prison inmates from Hawaii claim they got an unusual injury while imprisoned on the mainland: a dog bit them.

It was not a guard dog. It was a dog being trained by another inmate at the Diamondback Correctional Facility in Oklahoma and other mainland prisons as part of a rehabilitation program.

Inmates are retraining dogs from local shelters for adoption.

The dogs are supposed to be separate from the inmates, prison officials said.