The core banking system is fairly fragel, under some system a transfer of money to an account let's the other party keep transfering money to that same account.
In Sweden there are laws that if you transfer money to someone by accident they are required to return it and this is a Swedish bank account and a Swedish law firm. I have no idea if those laws would actually apply in this case though, seeing how I'm not a lawyer or anything.
On a related note it's nice to know those laws exist when you accidently pay the rent to your webbhost.
On top of that, above a certain dollar limit (don't know what it is in this case), this gives the Swedish court jurisdiction for criminal charges for the mastermind, for bank fraud.