Whoever got these wallets better sell them and get a good security company on rotation quickly before anyone find out who they are. Seems like wrench attacks been been happening a lot more the last year.
You just need to swap them for monero and then monero for litecoin or bitcoin again. Now you have anonymous, untraceable coins.
Not quite that simple, that’s vulnerable to an Eve-Alice-Eve attack. If $1B in BTC moves around in short succession the TXs can be linked easily. You need a mixer that splits up the amount to be paid out, and even then it needs to be done piecemeal.