Putting this here for now-- don’t think it really belongs in Cafe Society, but mods are welcome to move it.
I participate, infrequently, on a true crime MB, and I’ve had a couple of crime theories, one that probably isn’t true, but I think is interesting, and fits the facts pretty well, and seems like it would make a great novel. Another, also, that I think would have a lot of truth that would make sort of “reverse twist” ending.
My first idea is that Dan, otherwise known as DB, Cooper, and hereafter referred to as DC, was Canadian, and went directly to Canada after his parachute jump. The hijacked plane was from an airport very close to Canada-- not by any stretch the airport with the greatest resources in the US.
From what I can gather, the FBI did not reach out to Canadian banks they way it did to US banks in looking for the recorded bills. The FBI neither reached out to Canadian investigators immediately after the crime, working on the assumption that Cooper did not cross the border, albeit, it was as easy to do so as crossing from one state to another. No passport was required.
Cooper could have had the requisite military background, in Canada, something else which, as far as I can tell, was not investigated.
More: you could open an account in a Canadian bank with US cash in the 1970s, and “Dan Cooper” was the hero of a comic published by Belgium, only in French, and about a Canadian paratrooper, and distributed in Canada.
In my novel, DC speaks French, and makes it to Quebec in the immediate hours after the hijacking, after first crossing the Canadian border at Washington, State. He then lives “openly invisible” to the FBI.
My other idea is a Jack the Ripper novel.
Not so many details worked out here, but I’d just follow the timeline of the crimes as they happened, filling in reasons for things like changes in victimology-- he attacks a younger woman in the Mary Kelly case, and so much more savagely, because he is presented for the first time with the ability to work inside, for example-- Mary Kelly had a room, and all the others slept in doss houses.
My twist if you want to call it that, is that he cuts himself when committing one of the murders, and at the end is dying of sepsis from the wound. That’s why the killings stopped. He’ll die anonymously and be buried in a pauper’s grave, although I don’t go that far.
He has a rented room at the beginning, but loses it, and progresses to doss houses. The last things he owns are the clothes he wears and a set of knives he refuses to pawn.
At the end, someone asks his name, and I don’t supply it, but do have someone comment either that they’re never heard of him, or that they’ve got ten others with the same name. Just something to drive home the point that whoever he was, he probably wasn’t anyone famous at the time, which pretty much all people accused since have been.