river value bet or check?

[slik]

MP is loose passive. Button is unknown. What do I do on the river? I feared that button was on a flush draw, and that coupled with the fact that the ace could have hit him also made me check, intending to call. would betting and folding to a raise been better that check calling?

Ultimate Bet 5/10 Hold'em (6 handed) converter

Preflop: Hero is CO with J[img]/images/graemlins/spade.gif[/img], Q[img]/images/graemlins/club.gif[/img].
<font color="#666666">1 fold</font>, MP calls, <font color="#CC3333">Hero raises</font>, Button calls, <font color="#666666">2 folds</font>, MP calls.

Flop: (7.40 SB) J[img]/images/graemlins/club.gif[/img], 2[img]/images/graemlins/club.gif[/img], 5[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(3 players)</font>
MP checks, <font color="#CC3333">Hero bets</font>, <font color="#CC3333">Button raises</font>, MP calls, <font color="#CC3333">Hero 3-bets</font>, Button calls, MP calls.

Turn: (8.20 BB) 9[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(3 players)</font>
MP checks, <font color="#CC3333">Hero bets</font>, Button calls, MP calls.

River: (11.20 BB) A[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
MP checks, Hero ?
Final Pot: 11.20 BB