WASHINGTON (CNN) -- Former Deputy Secretary of State Richard Armitage was the source who revealed the identity of CIA officer Valerie Plame to syndicated columnist Robert Novak in 2003, touching off a federal investigation, two sources familiar with Armitage's role tell CNN. The sources said Armitage revealed Plame's role at the CIA almost inadvertently in a casual conversation with Novak, and it is not clear if he knew her identity was classified at the time. Armitage was not indicted by the federal grand jury that investigated the disclosure of Plame's name to Novak and other journalists. Deliberately revealing the identify...