It would be my belief this person is local to the area, and obviously after abducting JR felt un worried about being found to do what he did. I would assume it would take sometime to do that to a body, so he was not concerned about anyone "stopping by" so to speak....
This person is one sick SOB and dangerous, it is obvious he/she is toying with LE. I would be certain IMOO that he/she has done this before ....
Here is a thought I'm sure has been considered --
If the place where the remains were found is known to locals, and used typically as a place where photographers go... kids hang out etc....
Then what if he was prepared with something that would have made him blend in to that area quite easily? Perhaps he cased the area earlier with camera in hand or spray paint? Perhaps when he left the remains, he wasn't suspcious b/c he might have carried the remains in a tripod bag or a camera bag? We just don't know. But the easiest way to hide is to blend in. I'm betting that is exactly what the guy did. He blended in and therefore, no one noticed him.
Also, I'm going to say that LE seem quite convinced he is a local guy, and that someone would notice him changing his behavior or appearance. Someone who missed work, who never does. Someone who went out of town, never does.... they seemed to me to stress that he could be someone you work with, someone you know... even a relative.
From that, I suspect police think this guy has a family. I think they are thinking he has a spouse, and is hiding this from them. I think they think that whatever he changed is very subtle, and might be hard to notice, but they sure are urging people to be suspcious of any changes in behavior or appearance! They're basically saying, if he was late for work, or missed work, and never is, never does, or if he shaved, or suddenly grew a beard, cut his hair, dyed his hair, got a peircing, lost a piercing... any subtle thing that could easily be explained away by him... to call it in.
And you know what? People won't because they don't want to believe or even entertain the idea that their father, brother, spouse, relative, friend or co-worker could be *that guy* who did this to a little girl. People won't suspect him because he seems ordinary (if you listen carefully to what police said). People won't want to call because the person they call about might get mad at them and it could cause issues in their relationship with that person -- and police are right.
If someone calls in about a very subtle change in someone they happen to know or love, and it turns out it is NOT that guy... then ya, that guy they called about is going to be offended! you would be too if your loved ones thought it were possible that you were capable of this!!
But police seem convinced, that someone knows this guy, and knows him well enough to know something is / was off with him that day, and since this happened. And they need you to call it in if you noticed any changes in anyone around you! Even something small! Call anonymously, but for the love of god, call it in!
Best Case: you're wrong, but then you're assured that its NOT that guy b/c police will have ruled him out, thereby making you and your other loved ones, THAT much safer!! Then police can cross THOSE guys off their lists and move on!!
Worst Case: you're right, and you don't call it in, and he never gets check, and he keeps repeating this!!