I've considered that possibility as well. As I understand it, her bedroom was somewhat small but sufficient for three people to be in at the time the girls came home.
Let me ask this follow-up question. If these individuals were in the home were they there simply to kill or abduct Sherrill or waiting for Suzie to show up as well or were they simply rifling through Sherrill's belongings for valuables? If they were burglars who were there to steal valuables why would they leave so much money in Sherrill's purse but more importantly why would they stack the purses up on the steps to the sunken bedroom?
Is this normally what one might expect of these caliber of criminals? Offhand I would say they would want to do a quick in and out and be gone. Of course I am going on my own two personal experiences with burglars while living in Springfield. It was obvious they were burglars. As I understand the crime scene every effort was made to make it appears so as not to be seen as a burglary.
That being the case; not a burglary, then we have to necessarily conclude that they had a specific purpose in mind and that was to simply execute the intended victims. Wouldn't it have much simpler and quick to simply shoot them on the spot and leave the bodies? Without a traceable weapon and a small caliber weapon such as a .22 with a silencer it would have been virtually impossible to find the perpetrators. Certainly there would have been far less interest in this case because of its extreme unusual nature than a triple homicide that long ago would have been forgotten.
Of course I suppose this unusual case is what has led the various LE authorities to conclude this was a sexual assault although I haven't a clue what gave them that impression. So far as I know there was no forensic evidence leading to this conclusion. Some believe this is just a guess based on the logic of other common motives.
The possible struggle would logically have broken the globe.
People conclude that the lack of physical evidence and disruption of the crime scene means it was professional. I have never believed that. However it could have been planned. I think it was just limited to the two rooms. So control of the women was enough to not disrupt things. As far as the van goes, I know it doesnt jive with the known facts. I was just really acknowledging that if that area was blocked she would have drove in the other way. It was a last minute decision to go there and her mother didnt know she was coming home. I think sexual assault was the motive myself. I think the various agencies thought that because of that lack of evidence pointing to another motive. THe driveway being blocked is not my personal theory, but it would be one of the options. As far as three people keeping there mouth shut.......the death penalty would be quite the motivation to stay quiet.