I stumbled upon this looking for something to read in the back pages. This is very well written. I have enjoyed it and am sorry to see it unfinished. I gather that the letter murders must be the snuffing out of Muggleborns by Deatheaters. But why would the Hogwarts letters be left lying around. The Deatheaters certainly wouldn't want Muggles knowing about the wizarding world and the ministry would remove them (as well as obliviating any witnesses) to keep the "secret."
I hope you can bring yourself back to finish this. It is a very good read.