Does his behavior constitute fraud?

Such a thing is really outrageous, but I suggest you confirm the situation first, or it may be a misunderstanding. According to your authorization, you can only ask him for the evidence you have. If he refuses to return or cheat (pay attention to leaving evidence), you can accuse him of embezzlement. A huge amount can still constitute a crime. The crime of embezzlement is an absolute crime of neglect. As for finding someone else, it shouldn't be difficult. You know the name. I hope it helps you.