Nearly 60 years ago, a French town was hit by a sudden outbreak of hallucinations, which left five people dead and many seriously ill. On 16 August 1951, postman Leon Armunier was doing his rounds in the southern French town of Pont-Saint-Esprit when he was suddenly overwhelmed by nausea and wild hallucinations. It was terrible. I had the sensation of shrinking and shrinking, and the fire and the serpents coiling around my arms," he remembers. Leon, now 87, fell off his bike and was taken to the hospital in Avignon. Over the coming days, dozens of other people in the town fell prey to similar symptoms. Doctors at the time concluded that bread at one of the town's bakeries had become contaminated by ergot, a poisonous fungus that occurs naturally on rye. That view remained largely unchallenged until 2009, when an American investigative journalist, Hank Albarelli, revealed a CIA document labelled: "Re: Pont-Saint-Esprit and F.Olson Files. SO Span/France Operation file, inclusive Olson. Intel files. Hand carry to Belin - tell him to see to it that these are buried." F. Olson is Frank Olson, a CIA scientist who, at the time of the Pont St Esprit incident, led research for the agency into the drug LSD. David Belin, meanwhile, was executive director of the Rockefeller Commission created by the White House in 1975 to investigate abuses carried out worldwide by the CIA. Albarelli believes the Pont-Saint-Esprit and F. Olson Files, mentioned in the document, would show - if they had not been "buried" - that the CIA was experimenting on the townspeople, by dosing them with LSD.