For the past decade, poachers have killed rhinoceroses in the wild and in protected reserves around the world at alarming rates, threatening the survival of four of the world’s five rhino species.

The poaching is driven by a demand for rhino horns in southeast Asia that has grown nearly insatiable; so much so, experts say, that any living rhino – anywhere in the world – is now at risk of being killed.

Perhaps no rhino death illustrates that threat more forcefully than the killing of Vince, a 4-year-old male white rhino who was slaughtered this week inside his enclosure at a zoo outside Paris. The rhino – discovered by his keeper at the Thoiry Zoological Park on Tuesday – now holds the ominous distinction of likely being the first rhino to be killed by poachers inside a zoo, experts said..

“It’s an incredibly shocking and distressing occurrence,” said Crawford Allen, senior director of TRAFFIC North America, a regional office of the World Wildlife Fund. “It’s also a game-changer for zoos. They’ve woken up today and realized their world has changed if they have live rhinos in their collection.”

The Thoiry Zoological Park, which is 30 miles west of Paris, said on Facebook that its “entire staff is extremely shocked” by Vince’s killing. The animal was born in a zoo in the Netherlands in 2012 and arrived at Thoiry in March 2015, the zoo said.

The zoo pinned the killing on criminals who forced open a gate and two doors to gain access to the animal lodges.

Police said Vince was shot three times in the head. One of his horns was removed, probably with a chain saw, the zoo said. “His second horn was only partially cut, which suggests that the criminals were disturbed or that their equipment proved defective,” the zoo said.

For a new generation of wealthy buyers in China and Vietnam, rhino horns are a highly-coveted status symbol and an ostensible cancer-curing miracle drug and aphrodisiac