The hacker group that brought Sony to its knees is now threatening to hack CNN, the FBI warns. In a cryptic, menacing message posted online, the so-called 'Guardians of Peace' says: 'The result of investigation by CNN is so excellent that you might have seen what we were doing with your own eyes.' The group then offers the bizarre demand that the network 'turn over' Wolf Blitzer, the popular host of CNN's 'Situation Room.'