(CNN) Six baby seals have been found decapitated at a popular New Zealand bay, in what authorities described as a "brutal and violent" crime.

A tourist operator discovered the 11-month-old fur seal pups floating in tidal wash at Scenery Nook, near Christchurch on New Zealand's South Island.

They had apparently been killed and had their heads removed elsewhere, before possibly being dumped by boat for visitors to find, according to the New Zealand government's Department of Conservation (DOC).

Police have been called in to find the perpetrator, and the DOC is appealing for any recent sightings of boats in the area.

"Due to the disturbing, brutal and violent nature of this crime against defenseless seal pups, it has been reported to the police," Andy Thompson, DOC Mahaanui Operations Manager, said in a statement.

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