Even before crypto "if you're good you're good". People have always gotten away with these things. It's just usually because they either didn't make a mistake (very rare) or the authorities didn't care enough (very common).
I read the indictment. They were arrested and charged. We'll see how the defense plays out but from a read of the indictment they made plenty of mistakes and will (likely) end up going to prison given the conviction/plea rate of federal prosecutors.
Once convicted a federal judge can order them to give up the monero (as I said in my original comment). On top of their time in sentencing for the original crime they can be held indefinitely until they comply with the court order.
In the end they'll go to prison and the government will squeeze them for whatever they can get.