The post owl finds Hannah Bombay and delivers a letter. It's quite clearly a Hogwarts post owl, but the letter is on personal stationary. The letter is from Knox Greyfriar.9 October 2011
Hannah,
Our child is doing an excellent job wrecking havoc and seems particularly fond of chewing off the nibs of my best quills. I've ordered a quiver of new quills just for her. She yowls in the morning and I answer back. I don't know what either of us are saying, but I don't want to discourage her. Is this how it begins? I hope so.
By the way, I believe our mutual acquaintance Mr. Johann Storm has ratted you out.
He said to me not twenty-four hours ago that you have always spoken fondly of me. Now, had he not been a wizard of good reputation I would assume he was lying, but I do feel quite certain you are hereby guilty of common decency. I know that in pointing this out, it won't happen again.
But tell me, what nice things are you saying about me? I hope it's to do with my beard. I think it's quite fetching.
All my best,
Knox