Maybe there was other DNA in the bag he transported her in??
From Huffington Post article as updated 13/10/2011 (http://www.huffingtonpost.co.uk/2011/10/11/joanna-yeates-murder-tria_n_1004636.html)
I think he was already in her flat. She enters, takes off her boots and at some point realizes hes there (maybe hiding in the bathroom). She...
Maybe previous letters sent but who else has/has access to keys to the mailbox?
Congratulations and thanks, Ynot.
Thanks so much for this and all that you do.