Obama, McCain campaigns' computers hacked for policy data

WASHINGTON (CNN) -- Computers at the headquarters of the Barack Obama and John McCain campaigns were hacked during the campaign by a foreign entity looking for future policy information, a source with knowledge of the incidents confirms to CNN.

The source said the computers were hacked mid-summer by either a foreign government or organization.

Another source, a law enforcement official familiar with the investigation, says federal investigators approached both campaigns with information the U.S. government had about the hacking, and the campaigns then hired private companies to mitigate the problem.

U.S. authorities, according to one of the sources, believe they know who the foreign entity responsible for the hacking is, but refused to identify it in any way, including what country