Transcript for Manhunt underway for poachers at French zoo

That international manhunt for the poachers who killed a rhino at a French zoo. And stole its horn. Zoos across Europe are now on alert. ABC's Alex Marquardt is on the scene in France with the latest. Good morning, Alex. Reporter: Good morning, robin. These are the two remaining rhinos who are unharmed. We hear so much about rhino poaching in Africa but it's extraordinary to be talking about this here at a zoo in France. The director of the zoo here calling this an act of extreme violence that has never happened in Europe. This morning, officials at this zoo in the French town of thoiry stunned he at the attack that left Vince dead. His horn cut off by the poachers. They managed to break in Monday night despite it having surveillance camera. They were prevented from taking his second horn. Either because their equipment failed or they were interrupted. The zoo's other two rhinos left unha unharmed. The zoo's director says they're shocked and distressed by this unimaginable killing. Shocked entering into the park armed and killing animals. That's the first time. Reporter: Unheard of. Absolutely unheard of. Reporter: Now zoos across Europe on alert after what authorities say is an unprecedented poaching from a European zoo. Poaching is driven by demand for rhino horns in some parts of Asia where it's falsely thought to have medicinal purposes including curing cancer and acting as an aphrodisiac. In reality they're made of keratin, the same tear as human Finkel nails and hair yet a pound of rhino horn can fetch tens of thousands of dollars on the black market making it worth more than gold. The white rhinoceros once a thriving species is classified as near threatened in part because of the trafficking. In 2016 alone more than a thousand rhinos were poached for their horns. Last year our T.J. Holmes went on patrol with park rangers at the oldest game reserve in Africa. What's a bigger threat to your rangers, is it the animals or the poachers? It's the poachers. Definitely the poachers. They've got deadly weapons. Reporter: To the rangers combating poaching is like fighting a war. Some would say they're getting close to wiping the rhino off the planet. And you all are fighting that battle right now. We are trying because -- it's very bad. Reporter: Zoos now the newest battleground and American zoos being encouraged to review their own security protocols after the poaching. This certainly calls for concern and we have alerted our members to what happened in France and asked them to take additional precautions. Reporter: This is till very much an active investigation scene. The police are back there in the enclosure where the killing happened it trying to determine what weapons and tools were used. They'll also be combing through the surveillance video but for now there's no indication of who carried out this horrific crime. Robin. Thank you, Alex. Hopefully they will find out who. Joining us is Ron Magill, the communications director of zoo Miami. You have been at this work for a long time. How concerned are zoos here in the U.S. About this? We're all concerned now. I mean this is something that's never been seen in any zoo in North America, never seen in Europe. So this is I horrific low for this. It's really incomprehensible this could happen. What can be done to stop this from happening again? I know we've been talking about security needed to be upgraded anyway but what more can be done? You know, it's very hard, robin, because when you're selling something -- when something on the black market goes for over $27,000 a pound that's a very inspiration for people to do these things. The bottom line we'll increase security Ott our zoo and have 24-hour security anyway. They're trying to inject rhino horns with poisonous dye so they cannot be used for anything. The problem is to immobilize the rhino to do something they lost a rhino last year doing that, immobilization process so it's a difficult decision to make. They're being poached at a horrific rate, 2007, only 13. The last three years over a thousand rhinos each year poached. It's a huge trade driven by Vietnam to China and there is a pipeline between the two for rhino horns. It's difficult to stop. Would it be helpful to educate the public about it and let them know what's going on. Absolutely. Listen, rhino horn is nothing more than fingernail material. Compressed hair like a big fingernail growing. It has no medicinal qualities at all. This has been proven. It's just something that's believed to be an aphrodisiac and believe in some of the Asian cultures to cure cancer. It's a myth. To kill such a ma yes tick animal for a myth is horrific. We hair your outrage, Ron. Thank you very much. Part of the reason if you will remember a year ago we were in Africa on safari to talk about this problem of poaching and, T.J., you and I were both there and saw you talking to the park rangers trying to combat this problem. You also spoke to a poacher who admitted he killed 50 rhinos. This is an all too common problem in the wild. You're talking about people who don't have work who are just depressed when it comes to their financial situation. You telling me I can go out here, these animals are roaming around -- sometimes they only have to carry a bag. Go out with them to carry equipment and can get paid and feed your family. That's what you're trying to combat. We're talking about this market in Asia. They have campaigns where they have celebrities sitting there doing this, biting on their fingernail. You want to get high on rhino horn, just sit at home and do this. Just say no campaign in that's all you got to do. That's all it is. It's engranged in culture as this magic cure all and now it's a part of the culture and it's just -- it's a cool thing to ve on your table when you have a party. And we are wiping this animal off the planet for nothing more than your fingernail clippings. Crazy. Lends perspective. Coming up the victim of that

This transcript has been automatically generated and may not be 100% accurate.