25PLO river decision

[thisnamedoesntfi]

Villain in this hand I have seen before, but no real reads, seems to play 4 tables like myself. I have yet to tangle with him in any meaningful pots. But I have notes "min bettor", which I have down on quite a few players on this particular network.

I don't have HH but from my memory.....
Hero is MP $36
CO is a SS
BTN has hero covered
Villain SB has hero covered

Folded to hero who is dealt A [img]/images/graemlins/spade.gif[/img] 8 [img]/images/graemlins/spade.gif[/img]7 [img]/images/graemlins/heart.gif[/img]5 [img]/images/graemlins/heart.gif[/img]
Hero raises to 0.75, CO, BTN, SB all call

Flop(3.25)
2 [img]/images/graemlins/spade.gif[/img]6 [img]/images/graemlins/heart.gif[/img]9 [img]/images/graemlins/diamond.gif[/img]
Villain checks
Hero bets 2.50
CO+BTN fold
Vil. calls
Turn (8.25)
7 [img]/images/graemlins/spade.gif[/img]
Vil. checks
Hero bets 6.00
Vil. calls
River (20.25)
4 [img]/images/graemlins/heart.gif[/img]
Vil. checks
Hero?