The Town Council has been trying to trap the dogs after a spate of attacks on pets.
Trevor's owner, Darcy Davis, said his pet had been missing for three days before rangers found his body near the Telegraph Station.
"He'd been attacked by a mob of them and he'd been torn to pieces," he said.
"They (council rangers) couldn't track him down because his microchip had been ripped out.
"They couldn't actually find his location for a few days."