Knowldge of the scheme is irrelevant to a complaint for restitution based upon unjust enrichment. If a creditor can trace fraudulently approprated assets to a particular recipient, then the court can order that money restored on the theory that the money confirmed an unjust benefit upon the recipient, and it is only fair that the money be returned.
If you received money which was not the product of some profitable investment, but which was instead the product of someone else's deposit based on a misrepresentation of its use, then you are unjustly enriched at the depositor's expense, and you are obligated to return the money.
HOWEVER, if the creditor CANNOT directly trace its deposit to a particular recipient, then the law holds that the creditor is no more than an unsecured creditor as to the money, and is not entitled to restitution. So, if there are lots of intermediate transactions, then it's quite possible that no action for restitution will be possible, and the creditor(s) will just have to wait in line with all the other unsecured creditors to get their money back -- creditors which may include you. And, neither they nor you may ever see that money.
So, all is not lost here. The plaintiff has a pretty heavy burden of proof to meet in order to get a judgment of restitution against you. But, you'll have to defend vigorously.
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