Did the world's biggest banks collude to manipulate a key interest rate before and during the financial crisis?

From the Wall Street Journal online:

For the past year, law-enforcement officials have been investigating whether the U.S. and European banks understated their own borrowing costs, which are used to calculate the London interbank offered rate, or Libor. The investigators are now looking into whether the banks effectively formed a global cartel and coordinated how to report borrowing costs between 2006 and 2008...

Inside the Justice Department, the case is being pursued by antitrust and antifraud prosecutors, said people familiar with the situation. Criminal antitrust investigations typically focus on collusive behavior such as price-fixing and bid-rigging. A number of the banks involved in the probe have hired high-profile corporate-defense law firms...

http://online.wsj.com/article/SB10001424052748704547804576261120293347088.html