BEIJING —  Police were searching for the culprits behind the beheading and skinning of a rare Siberian tiger at a zoo in central China, state media reported Sunday.

The female tiger was found with its head, legs and skin missing Thursday morning at the Three Gorges Forest Wild Animal World in Yichang city in Hubei province, Xinhua News Agency.

It said the locks of the tiger's cage were broken and that police found four homemade anesthetic rifles near the cage.

"It is highly possible that the killer or killers broke into the room, anesthetized the tiger, opened the cage and then dragged the animal out of the room and butchered it," Xinhua quoted one unnamed official as saying.

Tiger skins are sold on the black market in China, and tiger parts are used in traditional medicines.

Calls to the zoo rang unanswered on Sunday. A man at the Forestry Bureau of Yichang city confirmed the killing and said an investigation was under way. He refused to give his name.

The WWF conservation group lists the Siberian tiger as "critically endangered" and says there are only about 530 of the animals alive in the wild. Most live in the far east of Russia or northeast China.

Hundreds more live in captivity. Xinhua said China has established breeding bases to help protect the animals.