I don't see how not finding DNA of either parent rules either of them out as the killer of the child. i admit i haven't followed every facet of thjis case but it still seems, to me, odd that some stranger enters and exits unseen, kills the child and then writes a ransom note--not caring that he/she could be discovered while composing such a letter. lack of DNA evidence doesn't mean they can be ruled out--it just means that they can't be ruled in at this time.