Read "Enemies" by Pulitzer Prize winner Tim Wiener. This is not that out of character for the FBI really.

http://www.amazon.com/Enemies-History-FBI-Tim-Weiner/dp/0812...

That's not quite accurate, if you read the history of the FBI [1], they have been an intelligence agency as long as they've been a law enforcement one (pre-1950s, when it was called the Bureau of Investigation):

http://www.amazon.com/Enemies-History-FBI-Tim-Weiner/dp/0812...

They pride themselves in the idea hardly no one in the American public is aware of this fact.

9/11 made them focus their intelligence abilities on terrorism but those capabilities were hardly new to the FBI.