Fears over poisonous water are preventing police divers searching a Dartmoor sinkhole for a possible missing man. It is thought he may have jumped a wall and fallen into the pool at Whitecleaves Quarry, Buckfastleigh, on Saturday. A Sea King helicopter from RAF Chivenor was called by police, who had been alerted by the ambulance service. A child aged under 10 had reported seeing a man jump the wall just before 8.30pm. The helicopter liaised with police and ambulance and used a thermal imager to search for the missing man. But there was no trace of a body on the edges or around the quarry and the crew felt one may be in the deep water of the sinkhole at the bottom of the quarry, Police divers are now waiting the outcome of toxicology tests on the water before they are allowed to search. Police speculated that perhaps someone had been trying to poison peregrine falcons nesting on the quarry face. pigeon fanciers intensely dislike these predators. The helicopter landed on the football field in Duckspond Road at 9.33pm and Pete Thornhill, of Elm Bank, took the dramatic picture shown above. 'It stayed in the field for about half an hour,' said Mr Thornhill. 'The pilot got out, ran to a waiting ambulance and talked to the driver, spoke to children who were getting too close to the helicopter, then lifted off. He landed again later. 'We could see lights on the quarry face and wondered if someone had tried to climb up to steal the peregrine falcon eggs.'