I am still reading my way through the information here (only page three of over twenty). But the little note pad I am using is filled up so I will share my thoughts, observations, etc. Now, and if anything is off base or disproved, I'm happy to eat my helping of humble pie.
-There is discussion as to the killer's intelligence, with the concensus being that the killer was more lucky than dumb. My argument against this is that intelligence does not equal meticulousness, nor does it mean well informed or free of compulsion.
From what I've read thus far, the killer left only two substantial clues behind--the palm print and the semen. Interestingly, the semen was not found on outer clothing, nor (GRAPHIC) inside the victim(s). And, of course, there are a ton of theories, many viable, that the semen may not even belong to the killer. As for the palm print, has there been any discussion as to the usability of the print for evidence and identification?
In any case, when it comes to the semen, the use of DNA as evidence is a relatively new science--the first person to be convicted of rape was only twelve years before this. The killer could have been unaware of the effectiveness of DNA evidence, or, aware that this DNA was not available for comparison, and would only point to him if caught. As for the palm print, there are a number of reasons why the killer might have missed or overlooked it.
The fact is, outside of these two pieces, this killer was able to stop two teenage girls, get them out of their car without a struggle, kill them, put them in the trunk, and leave the scene of the crime undetected and with few to no witnesses. I've not seen yet any talk of tire tracks, footprints, articles of clothing, or any other clues that would lead investigators to the culprit. I'm not saying this guy is a genius, but it would be, I believe, a mistake to call him dumb.
-I agree that the killer must have posed at some point as a police officer. However, as DD (who, let's face it, has done a lion share of the work here. Well done! i wouldn't have any notes without you) posits, the costume may have been simple, maybe just a flashing blue light.
I am skeptical. One idea I think would be helpful here is that the killer was ready to kill, and the victims were chosen at the time of the murders. I don't think this was planned before hand. What does this mean? This means that the killer had to be prepared for a host of contingencies and potential victims.
What I mean by this is that, yes, it is possible that two teenage girls might need only a flashing blue light to pull over and surrender all power with complete trust. But it is possible that the killer didn't even know he was going to be pulling over two teenagers, and someone older and more experienced needs a certain threshold of decorum to believe that the person pulling them over at the time is actually police.
I would think that at a minimum, the killer had flashing blue lights as well as:
1) A badge. License on the dashboard, window partially opened when the other window was closed (indicating that AC was probably being used), suggests that the girls believed that this was a cop even after they were pulled over and when he came to their window.
2) A sedan or vehicle that was at least similar in shape and appearance to the kinds of vehicles used by sherriffs and police in the area. Does anyone know what the local constables drove back when this happened? I highly belive that if this killer was posing as a cop, he's going to have a car of a similar make, model and color.
This also reduces the likelihood, in my opinion, that the white truck was involved as all descriptions suggest that there is no way that vehicle gets mistaken for a real police vehicle (unless they do use lifted pickups in alabama).
-I just want to show my support for the idea that the semen is not necessarily that of the killers. I also wonder if it is important to suggest that the semen could have been deposited post mortem. Granted, that would be much more difficult for the killer, but by my estimation, he had three and a half hours unobserved; a lot can be done with that amount of time. But it is important to keep an open mind to the idea that there was a consentual sexual encounter earlier in the evening (approximately between getting off work, and last time being seen alive is more than enough time) before the killings. This would give some gravity to the "being lost on purpose theory" which is addressed in my next point.
-It is possible that the girls were lost on purpose to meet someone without being caught. This would not make getting directions mandatory, however I don't believe that the rendesvouz would also be directly involved with the killing. Whatever had happened was done by 1130... the girls were on their way home at that point, and we should assume that if there was a tryst, it had been concluded at that point. If the tryst was going to end in murder, wouldn't that have come before the phone call home that was witnessed by the mother and daughter at the Big/Little?
-If the white truck is involved with the crime, I think it almost excludes the fake police scenario. My gut is telling me the truck isn't involved... the big thing being witnesses. It's there, caught on camera, and sees that there are two seperate parties with knowledge of each other. It can't be sure how long the two parties will stay together on the road, and the driver can't be sure he wasn't noticed, seen, and remembered. Of course, I'm not discounting the truck, it just doesn't... feel right.
-What feels best to me is military, potentially base police which would have access to blue light, badge, AND a sedan that is dressed up like a police cruiser.
But, like I said, I'm only three pages in. We'll see what else you guys have done. Good work the whole lot of you.