I am pretty sure it was Bethel and Brady eventually blamed himself for being stupid enough to throw it to him in the first place. Don't know if it was an interception, so much as a drop or non-catch on an important 3rd down.
There is something about it in the new book on Tom Brady - Moving the Chains. Both Brady and his father are quoted in the book.
What was said about Bethel was that he couldn't understand the offense or run the right routes. It was never said whether he was arrogant, stupid, lazy, or all 3 - just that he never got it.
