Canfield was killed when Martin and John Ray Falk, both inmates at the Wynne Unit in Huntsville, broke away from a work detail, stole a truck and rammed into Canfield while she was on horseback. The fugitives were caught within hours.
Martin already had been serving to 50 years for attempted murder.
Falk is awaiting trial on similar charges related to the officer's death. He'd been serving life for murder in 1986.
Canfield's horse had to be euthanized.