if these investors were unaware of the scam,
and they withdrew their money in good faith,
how would they be culpable?
If you unknowingly buy a stolen car, the police take it back just the same. And you’re SOL.
They wouldn't be "culpable" (they won't be prosecuted), but the courts will still take back the stolen money, which was transferred to them, and return it to the rightful owners.
This is a lawyer's dream. It is so complicated, that the money will all be eaten up by legal fees, and the lawyers will walk away with it.