I can't speak for anyone else such as Richard, but I think after looking at earlier maps, aerial photography from the 1960s, and statements from people driving on Drumm Ave at the time, it's now fairly clear that Drumm "Avenue" was an unpaved, narrow, single-lane dirt road build in the late 1800s and a through "road" (little more than a dirt path).
A criminal might have thrown caution to the wind and did an abduction on a busy street, but the way I see it is until the path, there was a 50-50 or better chance of being spotted....
... Richard, I know you don't think Welch did it, but with your knowledge of these types of crimes, statistically how to people without cars who just loose it and kill on the spur of the moment get rid of bodies?
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SteveP,
First, I do not know who might have abducted the Lyon sisters or killed them. There are a lot of potential suspects, Welch being only the most recent one considered.
To answer your question, I think that most people who "lose it" and kill someone on the spur of the moment tend to leave the body right where it fell, or perhaps move it only a short distance and leave it in the open. This is seen daily in homicides all over the country.
Those bodies which are NOT found immediately where the murder took place (but found later) often remain unidentified for some time after being found. These "John/Jane Doe" cases give some idea of how and where bodies are hidden. The thread on Websleuths titled Unidentified - or the case listings on the Doenetwork or other similar sites - indicate some of those hiding places/methods. Often victims are found in isolated areas, just dumped in rivers, hidden under brush, or even placed in shallow graves.
Of course there are also the very old cases of missing persons (such as that of the Lyon Sisters) which continue to perplex investigators. Even when someone confesses to a long cold case the body cannot be located for various reasons.
Perhaps a more foccused answer to your question might be to look at some of the potential suspects discussed or mentioned in this Topic area. Without just speculating on how one might have disposed of the girls bodies (assuming they were killed), consider other cases more definitely connected to each potential suspect.
For example, Hadden Clark was a resident of Montgomery County and he would be classified as a serial killer by just about any definition. His two known murder victims (for which he was convicted and sentenced to life in prison) were Michele Dorr and Laura Hoteling. Their bodies were eventually found in shallow graves in remote areas where he buried them and where he often visited or camped. He confessed to others in other states which he claimed to have also buried, but investigators could not find the bodies.
Other possible suspects used other methods of disposal of their known victims. Body disposal MO is something which has to be considered when trying to connect any unsolved case to a certain potential suspect, but it cannot be the only factor.
A careful and organized killer might have everything planned out in advance, including methodical disposing of his victims. But it is also possible that the organized criminal might encounter an interruption or obstacle to his plan and have to change things on the fly. Or, under the influence of drugs or alcohol he might on occasion become careless.
It is also possible that the killer gradually becomes more sure of himself and bolder in what he does, thinking that he is "lucky" or immune from police detection. Such a person might eventually be found and convicted of his latest murder, because of sloppy disposal of a body. Such a killer might remain undetected concerning earlier murders in which the bodies were more carefully hidden or buried.