"Bigfoot" hairs examined by the FBI were actually from deer.
Documents from the 1970s have finally been released revealing details of a short-live investigation into the elusive ape-like beast - the existence of which is yet to be proven.
A man called Peter Byrne wrote in an August 1976 letter: "Will you kindly, to set the record straight, once and for all, inform us if the FBI has examined hair which might be that of a Bigfoot.
"Please understand that our research here is serious. That this is a serious question that needs answering."
Responding in February the following year, the FBI's assistant director Jay Cochran Jr. wrote: "It was concluded as a result of these examinations that the hairs are of a deer family origin."
One of the first reported discoveries of Bigfoot dates back to 1811 when British explorer David Thompson found mysterious large footprints which he attributed to the beast.