It would of been unlikely that tower stars was holding A Q and hit the nuts with a straight, more likely Q 9 which would again have you beat nut again i think not with the earlier call and proberly hearts as well for a flush draw. my other conclusion would be that they were holding the fish hooks and hit a set. either way id of folded them aces after the flop on that bet even if it was a bluff it has too many possiblities..... my ultimate guess though would have to been hes on the flush draw or straight draw and doesnt want to see any more cards and put in an overbet to take the pot, if you hit the nut straight or even a set from here why would you go all-in?? you'd be better laying a trap and let more money come to you as usally the pre flop agressor would continue to bet.

remember most of the time strength means weakness and weakness means strength in poker