At least 30 dead green sea turtles were discovered on the shore of an isolated Japanese island; many of them had been stabbed in the neck.

On Thursday, locals on Kumejima island discovered after a low tide reveals the bodies.

According to the news website Mainichi, at least one fisherman acknowledged injuring the animals to remove them from the fishing nets.

Police are investigating allegations of animal mistreatment.

According to a story by the Mainichi, an anonymous fishing operator told a close source, “I disentangled some of the [turtles] and released them into the water, but I couldn’t free the hefty ones, so I stabbed them to kill them.”

Last week, local media claimed that police officers were dispatched to the location, although it is unclear whether any action has been taken.

Japanese authorities and global conservation organizations have identified green sea turtles as an endangered species.

They are known to frequent the seaweed and kelp beds off Kumejima, one of the tiny islands located approximately 2,000 kilometers south of the Japanese mainland, where conservation efforts are also underway.

After the turtles were discovered, marine biologists and other staff members from the island’s Sea Turtle Museum went to the shore, but the majority had already died.

Several had been stabbed at the base of their necks, while others had their flippers sliced. The museum’s photographs depict the animals floating in shallow water.

One museum employee told The Asahi Shimbun, “I have never seen anything like this before.”

This is incredibly difficult to comprehend.