It was Quirrell.

"You!" gasped Harry.

"Motherfucker! Oh, I did not see that one coming!" Shouted Amelia in rage.

Quirrell smiled. His face wasn't twitching at all.

"Me," he said calmly. "I wondered whether I'd be meeting you here, Potter."

"But I thought -- Snape --"

"Severus?" Quirrell laughed, and it wasn't his usual quivering treble, either, but cold and sharp. "Yes, Severus does seem the type, doesn't he? So useful to have him swooping around like an overgrown bat. Next to him, who would suspect p-p-poor, st-stuttering P-Professor Quirrell?"

"Well, played asshat well, played," said Amelia.

Harry couldn't take it in. This couldn't be true, it couldn't. "But Snape tried to kill me!"

"No, no, no. I tried to kill you. Your friend Miss Granger accidentally knocked me over as she rushed to set fire to Snape at that Quidditch match. She broke my eye contact with you. Another few seconds and I'd have got you off that broom. I'd have managed it before then if Snape hadn't been muttering a countercurse, trying to save you."

"Snape was trying to save me?"

'Well, shit."

"Of course," said Quirrell coolly. "Why do you think he wanted to referee your next match? He was trying to make sure I didn't do it again. Funny, really... he needn't have bothered. I couldn't do anything with Dumbledore watching. All the other teachers thought Snape was trying to stop Gryffindor from winning, he did make himself unpopular... and what a waste of time, when after all that, I'm going to kill you tonight."

"That would be tremendously ambitious of you." Harry glared at Amelia.