I'm not at all certain, Alice. About the murder, I mean. I can't make sense of what Harry told me. He said that Voldemort told him he had a present for him, and he held out the very first Snitch Harry ever caught in a Quidditch match. He wanted him to hold the Snitch and kill Ridley. (Though from the sound of it, wanting to murder Ridley is a desire not exclusively Voldemort's. Tell Frank to tell her that her 'lover' says hello.)

Anyway. There was something about a potion that he wanted Harry to drink after the murder was done and a bunch of other instructions but Harry'd already decided he wasn't having any of it. He said he faked the spell as best he could, figuring it would be better to 'fail' than to refuse.

As for the wands, Allie, like I said, I think the description sounds like Priori Incantatem. I've heard of it but never seen it. (I mean to say, other than deliberately casting the charm. I've seen that. But I've never seen it happen accidentally.)