Hello all. Longtime lurker, blue-moon poster here. Not an expert by any means but I will earn my BA in Criminal Justice this Spring. My studies have primarily focused on sex crimes, sexual predators, the psychology of sexual violence, forensic investigation/entomology and victimology. I hope to someday work with the FBI or local state police in finding missing persons and those responsible for the ones not found alive.
I totally agree with the idea that staging the bikes and purse in this way would make it appear as if they had drowned, because that is exactly what everyone first thought. This bought the offender(s) a lot of time by keeping resources focused in what I think is a "red herring" area, an area in the opposite direction from where they were eventually found.
I've also given the location and position of the bodies a lot of thought. First, I'm going to work off of the assumption that they were alive and walking upon entering the area where they were found. I am tempted to discard the idea that they were carried in because they obviously still had their shoes with them if the shoes assisted in identification. Flip flops would fall off too easily en route if she was being carried (don't know which one was supposed to be wearing flip flops), unless they were wrapped in something; however, we have no indication that the bodies were in any way covered, or wrapped. 5 months is long enough for complete skeletalization but not long enough to fully erode the most common coverings of plastic, fabric, or carpet. So, for this reason, I'm thinking they were walked into the area on foot.
Now as to the position of the bodies, from the aerial photos we do know they weren't exactly right next to each other, but instead were more than 20-50ft apart at least (guesstimates based on google maps distance legend, please correct if someone knows exact distance). (Graphic content warning #1): While it is true that vertebrate scavengers can sometimes move bodies, that's usually much larger carnivorous animals like very large mountain lions, but even then most still wouldn't. But smaller animals like coyotes are more likely to tear away and snatch a single limb than move an entire body. So I am thinking they were initially separated on purpose, not separated by scavengers. So, what does this say to you in terms of the number of offenders? (Graphic content warning #2): To me it says there were two, one for each offender to have all for himself. If one person had both girls, he (or she, whatever) would have had to keep them close to him to remain in control, by threat of weapon or by threat of hurting the other girl. Further, what motive would he have for dealing with them separately, many yards apart? To take two girls, the psychopathy is likely such that a single predator would treat them as a pair to remain together. He would have no reason to dispose (sorry for the term) of one and then move to a second location to dispose of the other (even if very close by). My thought is that they were separated because (Graphic content warning #3) they were being assaulted separately so as to afford some semblance of privacy for each offender. If this is the case and there are two offenders, then I think we can eliminate a husband/wife or bf/gf scenario because that type of relationship is usually the type where one partner (usually male) is dominating the female and controls her to participate. In this instance the opposite gender pair acts the same as a single predator because the submissive is only acting as an assistant to the main offender. So the distance between the bodies, IMO, instead points to offenders of the same general status and gender, with one not overtly controlled by the other.
As for motive, the distance between the bodies supports my theory that sexual assault was the primary motivation for the abduction. Had the girls simply been executed for drug debt or snitches' payback, why separate them to execute them? Turn them around and shoot them at the same time and get out of there, leaving as little evidence behind as possible.
As for age of the offenders (if in fact there was a pair), then I'm venturing an educated guess that they are younger males (>16 but <25), perhaps a local pair of brothers or best friends, with hunting or fishing experience and a lack of supervision or strict schedules during the summer months. I think older males would have concealed the bikes rather than leave them and risk leaving prints or DNA. Younger males wouldn't have a place all their own to commit the assaults/murders nor to conceal the bodies or the bikes.
Again, just my opinion.