Michael Ornstein is the name to know. As first reported by CBS's Mike Freeman, Ornstein—a close friend and confidant of Sean Payton—Ornstein on at least four occasions pledged his own money to the Saints' defense's bounty fund. In 2009, $10,000 toward knocking an opposing quarterback out of the game. In 2011, two separate contributions to targeting the quarterback. And on at least one other occasion, Ornstein pledged his money in an email to Payton, which spelled out the details of the bounty program.
The NFL knows this because it has that email, a highly incriminating paper trail that makes it impossible for Payton to argue his innocence, or for the Saints to claim the bounty never left the locker room. It might be the single most damaging piece of evidence, based solely on Ornstein's history.
Once upon a time, Ornstein was an NFL executive in charge of marketing. That was until he attempted to defraud the league out of $350,000. Ornstein conspired to submit fraudulent invoices to Los Angeles based manufacturers, pocketing the money and never providing the NFL with the merchandise they were led to believe they had purchased. He pleaded guilty to mail fraud, and served four months home confinement, five years of probation, and paid the NFL $160,000 in restitution.