The Department of Mysteries was obviously the place to start. Harry took it upon himself to start talking to some of the assistants in the department. It was unlikely they'd seen anything, but the people who handled the minutia of the day were often the ones who had a better idea of what was going on.
He was halted by a voice, one that came form a slightly older woman with dark hair and a rather business-like expression. "Possibly," Harry responded. "I'm..." he hesitated a moment, and then just forged ahead, continuing as most any Auror would. "I'm Harry Potter and I'm here to ask some questions about what's happened. May I have some of your time, please?"
If he started out politely, there was a better chance of getting polite responses back, something he noticed not all Aurors did. He supposed it didn't matter if they all got results.