It is reported that the hackers behind the Twitter attack have now claimed responsibility.
‘Scriptkiddies’ took control of @foxnewspolitics - a bona fide account of the US news service with 33,000 people following it - at the beginning of 4 July, which is a public holiday in the US for Independence Day.
People following Fox’s politics feed account would have seen the shocking hoax posts that claimed the President was dead appearing from 2.43am EDT (Eastern Daylight Time), with hundreds of them forwarding this on to their followers.

Fox News politics’ account had been inactive for three days before the group initiated the hijack posting “regained full access to our Twitter account”.
The hackers then continued: “Barack Obama has just passed. The President is dead. A sad 4th of July, indeed. President Barack Obama is dead.”