(CNN) The FBI analyzed a sample of alleged Bigfoot hairs in the 1970s "in the interest of research and scientific inquiry" that turned out to be deer hairs, according to newly released records.

Peter Byrne, then the director of the Bigfoot Information Center, wrote a letter in 1976 asking that the FBI "set the record straight, once and for all," on a previous instance of the bureau purportedly analyzing hair that was not identifiable as "that of any known creature on this continent."

FBI Assistant Director Jay Cochran, who helmed the bureau's laboratory division at the time, responded that he was unable to find any records of such an examination. Byrne, touting his group's affiliation with the Academy of Applied Science in Boston, requested an examination of what he saw as an exciting new sample.

"Briefly, we do not often come across hair which we are unable to identify and the hair that we have now, about 15 hairs attached to a tiny piece of skin, is the first that we have obtained in six years which we feel may be of importance," Byrne wrote.

Cochran responded that while the FBI laboratory focused on criminal investigations, "occasionally, on a case-by-case basis, in the interest of research and scientific inquiry, we make exceptions to this general policy."

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