Following the murder of two guards by illegal goldminers, scientists have been evacuated from a research station in the Nouragues nature reserve in French Guiana. The assassins were caught last week in Régina, a village lying 40km from the station.

The bodies of Domingo Ribamar da Silva and Andoe Saaki (‘Capi’) were found on 18May at the Arataï ecotourism centre where they worked, a few kilometres from the Saut Pararé and Inselberg research sites — all run by France's basic research agency, the CNRS. They had been shot, and the centre ransacked.

Alain Pavé, the head of CNRS in French Guiana, ordered the temporary closure of the research station the day after the discovery of the bodies. Fourteen staff and their equipment were evacuated by helicopter to Cayenne, 100km away. The gendarmerie is protecting the few remaining staff, and the sites’ facilities. The research station will not be reopened until security can be guaranteed, says Pavé.

“Apparently this murder is deliberate, probably to chase the scientists and managers of the Nouragues reserve from the area,” says Pierre Charles-Dominique, the tropical ecologist who heads the research station.

The miners, or ‘garimpeiros’, most of whom come from neighbouring Brazil, have been a constant security concern for scientists, he adds. His station was ransacked by miners in 2004. The thieves made off with equipment worth €75,000 (US$100,000), and delayed a major research project (see Nature 430, 127; 200410.1038/430127a).

Illegal goldmining is a growing problem in the reserve, says Patrick Jansen, an ecologist at the University of Groningen in the Netherlands. The miners cause substantial ecological damage: they suction riverbeds for gold nuggets, fell trees, and pollute waterways with mud and mercury.

Before the recent murders, scientists at the reserve were preparing to celebrate completion of the project delayed by the 2004 ransacking. The Canopy Operation Permanent Access System (COPAS) is designed to give scientists unprecedented access to the canopy of a tropical rainforest. It consists of a huge helium balloon and basket, which allows two scientists at a time to move vertically and horizontally within the canopy along a system of cables. Domingo and Capi had lunched with the COPAS research team at Saut Pararé the Saturday before they were killed, researchers recall, as they put the final touches to the treetop system.

A balloon will give scientists access to the forest canopy once work resumes. Credit: R. LEGUEN

All scientific work has now been put on hold. After the 2004 ransacking, the gendarmerie stepped up actions against the miners, introducing helicopter missions to find and destroy the mining sites, and arrest the miners, for example. But Charles-Dominique says that is not enough. “We cannot continue our research without a permanent military guard at the entrance of the reserve, and strong repressive action throughout the park,” he says. And that's no easy task in the vast forest.

Catherine Bréchignac, president of the CNRS, visited the centre on 25 May, as part of a scheduled visit to inaugurate COPAS. In response to the fears of some researchers that the station might be closed, she says “certainly not!”. After discussions with local government, she promised that the centre will be protected by the gendarmes and the military until the CNRS finds a private firm of armed security guards to assist it.

“I made the decision last night: two murders is inadmissible, we can't let visiting scientists work under such conditions,” she says. “I don't know much it will cost, but the science here is very important. The CNRS is committed to it and we will pay whatever it takes.” As Nature went to press, scientists were due to return to the station on 30 May, and COPAS will now be officially launched next week.

Still, the incident has left researchers badly shaken. Ecologist Pierre-Michel Forget worked at the station from 1984 until 2003, when he decided that the situation was too dangerous and returned to his native France. “Not everyone agreed with me in the scientific community,” he says. “But today, unfortunately, I see that I was right to do so. We often stayed at the Arataï river camp when reaching the forest and the station by boat. This could have been me.”