... I don't buy that Sam could have smelled so bad that all three sets of "civilian" witnesses who he encountered in the hours between 4:30 and 10:00 on Friday morning found the smell overpowering, but would have "just not smelled bad enough" to raise notice during his separate interactions with law in the early hours of this same day. It just seems weird that the civilians all noticed while not seeming to have raised a flag for law enforcement.
Note that by mid-afternoon on Friday, when the bodies were first discovered at the house, at least one officer not only noticed the smell but recognized it as the smell of "what he believes is a decaying body":
http://www2.timesdispatch.com/rtd/news/local/crime/article/FARM27G1_20090926-195801/295730/
When I first posted a couple of days ago, I mentioned that I believe the first three murders were probably committed overnight on either Monday/Tuesday (14th/15th) or Tuesday/Wednesday (16th/17th). If this guess is right, it would mean that the two girls and Emma's mom would have been dead for just 12-36 hours during the time that Mel's dad was outside the house on Wednesday afternoon, but 60-84 hours by the time the smell from the house [as opposed to the smell from Sam] was obvious to law enforcement two days later.
I'd be curious to know how warm the weather was in Farmville that week, and which days Sam was noticed by others on the streets and out at the grocery store all by himself? My "simpler is better than more complicated" theory of the crime is that Sam really did NOT spend that much time alone in the house with the bodies (perhaps just from the early hours of Wednesday morning to late Thursday evening, maybe a day more than that). But he smelled terrible enough at least for the civilians to notice because by that point possibly just because he had not slept in at least two nights and had been sweating profusely in unchanged clothes, partly because he was freaked out over what he had already done and realized that he had no viable plan for what comes next, and perhaps even more "extra smelly" due to the warm weather - along with proximity to the decomposing bodies.