JK Rowling: secret slasher?

I don't count Rowling's interviews as spoilery; I'm only cut-tagging because she mentions a new character in book 7 as a romantic interest of Dumbledore's, even though it's not specifically mentioned in the book:

( Dumbledore was gay )

Blood Ties

( Spoilers for this week's ep and also slight spoilers for the book Blood Trail )