Writing the ransom note on their notepad would be a great way to avoid any telltale evidence from your own house being left behind. How many killers have been caught by the police finding the same type of notepaper in the suspects house, a practice copy, etc.?
I don't know how or why - heck - I don't know how Elizabeth Smart's kidnapper did it, how Couey pulled it off in such a small house. Maybe someone close enough to the family that he figured he could explain his presence away if caught. Maybe someone who was in the house earlier, grabbed the notepad and returend it. Maybe just plain nutjob with delusions of godhood.
But, DNA in the panties matching DNA in the tights tells me we have the DNA of the killer, one of them at the least, and to me, that's the end of the story. I wonder - anyone think two killers are possible? One more interested in kidnapping, writing the note as the other, a pedophile, takes JBR from her room, and goes too far, too fast?