Popular bitcoin exchange Bitfinex has been hacked and the site has been taken down while the exchange investigates exactly what happened and cooperates with law enforcement.

Read more: http://bitcoinx.io/news/articles/bitfinex-hacked-exchange-goes-offline-during-investigation/

Update:

Confirmed: $61.8 million stolen from Bitfinex in exchange heist
Read more: http://bitcoinx.io/news/articles/confirmed-61-8-million-stolen-from-bitfinex-in-exchange-heist/