Benjamin
I've been poking around Law Enforcement today and the official story- that someone was trying to get the Harry Potter spell out of the DOM, Thicknesse found them, a fight ensued, he was killed and the murderer/thief, a member of the Order, got away clean, is what they actually believe.
I haven't heard anyone mention that Harry Potter is suppose to be out of the mirror, so the Order going after it makes very little sense. But I'm not going to remind anyone.