MORRO BAY, Calif. (AP) — California authorities are investigating the fatal shooting of a protected southern sea otter that had been rescued and returned to the ocean last year.

A southern sea otter. (U.S. Fish & Wildlife Service)

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The state Department of Fish and Wildlife said Tuesday that the dead otter was found floating in Morro Bay in September and a necropsy determined it was killed with a pellet gun.

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A numbered tag identified the animal as an otter that had previously been found tangled in a fishing line. It was rehabilitated and returned to the wild in July 2016.

The department says the killing was the latest in a rash of sea otter crimes along the stretch of coastline between San Francisco and Los Angeles.

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A skinned otter was found in September. Three otters were shot to death in August 2016.