Leprikawn-
This is exactly what I thought after reading Stalemate. Bindner is not dumb at all-if anything, he is a genius. He loves the riddles, he loves toying with police and families. I remember in the book he visited Sharon, Michaela's mom, and often kept in touch with Amber's mother. I believe Amber's mother has always believed deep down Bindner, did it, that is why she kept corresponding to his letters. The way he wrote to her was more than a concerned citizen trying to help or play detective. There was something more there...kinda like a "haha, I have the power and know what happened" type of deal.
I also do not believe he would be able to committ another crime, because he was in hot water and under constant survaillence-he did not have the option anymore to do so.
With how obsessed he was about Angela Bugay's murder, I believe if he took Amanda and Amber, he would have put them in a vicinity meaningul to him such as an area by Angela's grave, which would also match up with the dogs tracing BOTH the girls scents to the grave.
I just feel for Amber's mother because with Anderson's confession and him being deceased, I do not believe her case is being actively investigated. The only way I would ever believe he did it is if Amber was found where he said he put her, which she has yet to be found.
I feel in my heart Bindner knows what happened, and I think Amber's mother still feels the same. I feel for her because all she wanted was to put her daughter to rest. And now she is stuck with a possible false confession, no Amber, a possible suspect, whom she thought did from the beginning, out and free, and a case that is at a Stalemate.
I have all the admiration in the world for Amber's mother, i don't believe she will ever stop searching, no matter what the possible outcome could be.