Rogue intern or bitter staffer?

I had to crack up when I read this article from the AP:

Nobody expects to get a letter from a member of Congress that ends with an expletive.

But that's what happened when Rep. Jo Ann Emerson, R-Mo., recently corresponded with a resident of her southeast Missouri district. The letter ended with a profane, seven-letter insult beginning with the letter a - "i think you're an ..."

Emerson says she can't explain how the offensive language made it into the last line of the letter, which otherwise reads like a typical response to a citizen's question about last year's testimony of oil executives before the Senate Commerce Committee.