[phish]

While the hand is being played, verbal declarations are binding. In other words, if someone bets and another person says "I fold". His hand is dead.
But once all the cards are out and action is finished, now only the cards matter. Whatever you say makes no difference. However, if I were the floor, I would rule in the AJ's favor since that is in keeping with the spirit of the game whereas the other guy was obviously pulling a scumbag angle.
But technically the scumbag is right. He has the only live hand and so he should get the pot. And in my opinion, the fact that other players saw the hand shouldn't matter if the scumbag claims (lies) that he himself didn't see it.
(You can't award pots based on a what other people at the table say they saw (after all they could all be collusive buddies). The loser has to see the winner's hand, acknowledge it and muck his own hand before the pot can be awarded.)