Fine to raise this river?

[Deamon2]

This is my second hand with the table and with villain. His play reeks of WA/WB, but I'm not sure he knows it since I don't know if he has a clue yet. Does anyone find a raise on this river?

Party Poker 0.5/1 Hold'em (6 max, 5 handed) converter

Preflop: Hero is UTG with A[img]/images/graemlins/club.gif[/img], K[img]/images/graemlins/spade.gif[/img]. MP posts a blind of $0.5.
<font color="#CC3333">Hero raises</font>, MP (poster) calls, <font color="#666666">2 folds</font>, BB calls.

Flop: (6.50 SB) A[img]/images/graemlins/diamond.gif[/img], Q[img]/images/graemlins/spade.gif[/img], 4[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
BB checks, <font color="#CC3333">Hero bets</font>, MP folds, BB calls.

Turn: (4.25 BB) 9[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
BB checks, <font color="#CC3333">Hero bets</font>, BB calls.

River: (6.25 BB) 7[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">BB bets</font>, <font color="#CC3333">Hero ????</font>