There are all sorts of individuals who have obsessive tendencies, they know no bounds when certain things strike their fancy. I hesitate to offer any theories as I know many are want and even driven to do.. however, knowing he was a teacher..
Was he rejected by the mother at some point perhaps and killed the daughter to get back at her? If he followed the family to Georgia as mentioned or a Georgia connection somehow existed, it may show just how sick on an individual the suspect might have been.
We shall have to wait and see how this plays out. I won't go any further than that one and I would hope folks would restrain themselves from going to over the top as well.
Remember Silence of the Lambs?
"You covet what you see."
This suspect may have seen JonBenet and coveted her. Wonder if he attended beauty pageants for little girls.
This has probably already been mentioned on this thread, but it has been reported that there is DNA in the little girl's underwear. It may be that a DNA match will be possible.
It would be quite a blow to all the amateur sleuths in the world if this man's handwriting resembles Patsy Ramsey's.