The FBI released 22 documents from the records vault on Wednesday detailing the agency’s research on Bigfoot. The documents, which are dated from 1976 to 1977, show that an analysis was done on a sample of hair believed to be from the big man—in the woods—himself. Peter Byrne, then director of the Bigfoot Information Center and Exhibition in The Dalles, Oregon, wrote to the FBI requesting that the agency’s lab test 15 unidentified hair samples attached to a piece of tissue. The FBI agreed to test the samples “in the interest of research and scientific inquiry,” according to a reply sent by Jay Cochran, then assistant director of the FBI’s Scientific and Technical Services Division.

The FBI examined the hairs through “transmitted and incident light microscopy,” according to the documents. “The examination included a study of morphological characteristics such as root structure, medullary structure and cuticle thickness in addition to scale casts,” Cochran wrote. “The hairs were compared directly with hairs of known origin under a comparison microscope... It was concluded as a result of these examinations that the hairs are of deer family origin.”