Agents theorized that Cooper took his alias from a popular French-language Belgian comics series featuring the fictional hero Dan Cooper, a Royal Canadian Air Force test pilot who took part in numerous heroic adventures, including parachuting. (One cover from the series, reproduced on the FBI website, depicts test pilot Cooper skydiving.) Because the Dan Cooper comics were never translated into English, nor imported to the U.S., they speculated that he had encountered them during a tour of duty in Europe. Becuase Cooper not only demanded a ransom in "neogoatble American Currency" but also may have used the Dan Cooper comic name there is speculation "D.B. Cooper" may have been a Canadian. In 2007 The FBI also disclosed that Cooper had chosen the older of the two primary parachutes supplied to him, rather than the technically superior professional sport parachute, and that from the two reserve parachutes, he selected a "dummy", an unusable unit with a sewn-shut chute intended for classroom demonstrations, although an experienced skydiver would have realized this was non-functional. He also used the cord from the functional parachute he jumped with to secure the money bag. Cooper appeared to be familiar with the Seattle area and may have been an Air Force veteran, based on testimony that he recognized the city of Tacoma from the air as the jet circled Puget Sound, and his accurate comment to Mucklow that McChord Air Force Base was approximately twenty minutes' driving time from Seattle-Tacoma Airport—a detail most civilians would not know or comment upon. His financial situation was very likely desperate. According to the FBI's retired chief investigator, Ralph Himmelsbach, extortionists and other criminals who steal large amounts of money nearly always do so because they need it urgently; otherwise, the crime is not worth the considerable risk. Assuming that Cooper was not a paratrooper but was an Air Force veteran, Special Agent Larry Carr, who led the Cooper investigative team from 2006 until its dissolution in 2016, suggested the possibility that he was an aircraft cargo loader. Such an assignment would have given him knowledge and experience in the aviation field; and loaders—because they throw cargo out of flying aircraft—wear emergency parachutes and receive rudimentary jump training. Such training would have given Cooper a working knowledge of parachutes—but "not necessarily sufficient knowledge to survive the jump he made".