"Okay, so... Possible irrational hatred towards muggle-borns.  Possible but unconfirmed hatred towards women.  May or may not fit the description of the person Cho Chang saw Hannah speaking with, and we have nothing to connect him to the witch from the Apothecary.  Likewise, we have no evidence whether he knows Dolohov’s curse.  Do you think we can get that from Dolohov?  Find out whether Goyle Sr. knew the spell and could have taught it to his son?"