On August 2nd the Hong Kong-based Bitcoin exchange Bitfinex was compromised for roughly $70 million worth of Bitcoin. According to sources, the attacker managed to drain the exchange through its multi-signature security gaining 120,000 BTC from the breach. Now the exchange is trying to reach out to the responsible party in an attempt to get its customers Bitcoin returned.
https://news.bitcoin.com/bitfinex-seeks-bitcoin-thief/
https://news.bitcoin.com/bitfinex-seeks-bitcoin-thief/
Most likely the thief/hacker won't returned the stolen bitcoin, in fact i doubt the thief/hacker would communicate "anonymously" 
Of course,the thief is possibly enjoying his loot,why he should returned.
I do not know if the report is correct, or they just giving a false hope to their angry clients.This is a big breach amounting to $70 millions.There should be a strenuous investigations and let the perpetrators face their wrongdoings.
Is there a possibility that it is an inside job?