Bitfinex should negotiate with hacker. Offer $10 million to return the stolen bitcoins and drop investigation.
Yeah, this could be done. However I think hackers will not accept the offer, because they prefer to earn much money instead of having to return all funds they have get and given only a small portion of the money to them. But it also depends on how bitfinex the hacker in the negotiation to seduce, hopefully this issue was quickly completed and running as before
Reasons hacker might agree to negotiate:
1) The advantage of not being investigated might outweigh the difference in lifestyle between having $10 million and $60 million.
2) If he keeps a portion of his settlement in BTC, the price will rise after she agrees to settle.
3) If he takes a long position in bitcoin before agreeing to settle, he will profit.
4) He will be seen as a hero by many instead of a theif and will be sought after for security advice.
5) He will be able to convert his BTC to USD easily.
The idea isn't that bad actually, but these hackers don't really care if they have the feeling they are anonymous enough, with plans to somehow mix their coins in a matter of a few years. If they got that in their mind, then they will surely not turn more than $60 million into $10 million. I don't even think it's allowed by law as there will be an ongoing investigation.