This looks pretty odd. But check calling a large bet on the flop and then putting down a large bet on the turn and the river I think you are beat. People don't generally bet that hard with just one pair. (for one pair - unless maybe he has the overpair and slow played it preflop)

Unless you have a table image that you always put down a bet after being the preflop raiser. Sometimes people will check call the flop and then bet the turn to try and bluff you out without a hand or bet with a marginal hand. But that doesn't explain the river bet.

The other possiblity is that the villain is a complete maniac. Sometimes people start a bluff and they can't stop it. They feel that they have to win the pot otherwise their first bluff is a loss.

The only reasonable holding the villian could have that you have beat is 99 88 77. Or if he is a poor player maybe he had two pair with 64, then he just made a mistake on the river because it got counterfeited.

With his vpip could he could have the straight, trips/full house on river.

edit:
If he is loose aggressive postflop (that would match his aggression factor), then he could have been on the straight draw and then bluffing the busted straight draw on the river. Or some combination of a pair and straight draw. But if he has a pair I think it would be better to check the river.