Tricky... Have you thought about sitting your DD and you DS down at the table and speaking to the two of them at once?

Tell them that no-one is in trouble, but you know one of them did it and you need to know who. Also, you want the money back, as it belongs to their younger sibling and it's simply not fair... and in future, if they want extra money, perhaps they could do some chores or jobs around the house (weeding, mowing the lawn, dusting etc).

I think that treating them like adults is the best way to do it. And once you have the truth, be understanding. Being a teenager is such a hard time.

Celsie. xoxox