The FBI took possession of the placard and investigated its origin. The investigation confirmed that the placard was consistent with having come from the 727’s aft stair, and that its location fell within the range where Cooper was believed to have exited the aircraft.
This was not a breakthrough in the sense of identifying Cooper or establishing his fate. But it was confirmation that the investigation’s general geographic focus was not wrong—something from Flight 305 had come down in that region of Washington. Combined with the later Tena Bar money find, it represents the only physical evidence that has been found outside the aircraft itself in connection with the case.
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## Attempts to Profile the Hijacker
The Cooper case was one of the early cases in which the FBI attempted to develop a behavioral profile of an unknown subject. The Behavioral Science Unit at Quantico, which was developing the science and practice of criminal profiling in the early 1970s, applied its methods to the Cooper investigation.
The profile that emerged suggested a man with military experience, possibly with parachuting background, likely with some connection to the aviation industry or knowledge of aircraft operations. He was assessed as organized, calm under pressure, and apparently experienced at executing plans under stressful conditions.
These assessments drove the direction of investigation for years: the bureau focused substantially on men who had military parachute training, particularly combat veterans from Korea or World War II who would have been in the right age range in 1971. The demand for four parachutes was interpreted—consistent with professional military thinking—as reflecting an understanding that authorities might sabotage a single chute, and that demanding four made interference more difficult.