Overpair vs River Scare Card

[jmumm]

Full Tilt 0.50/1 Hold'em (9 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

Preflop: Hero is MP2 with K[img]/images/graemlins/club.gif[/img], K[img]/images/graemlins/spade.gif[/img].
<font color="#666666">1 fold</font>, UTG+1 calls, <font color="#666666">1 fold</font>, <font color="#CC3333">Hero raises</font>, <font color="#666666">4 folds</font>, BB calls, UTG+1 calls.

Flop: (6.50 SB) 6[img]/images/graemlins/diamond.gif[/img], J[img]/images/graemlins/club.gif[/img], Q[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(3 players)</font>
<font color="#CC3333">BB bets</font>, UTG+1 calls, <font color="#CC3333">Hero raises</font>, BB calls, UTG+1 calls.

Turn: (6.25 BB) 3[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
BB checks, UTG+1 checks, <font color="#CC3333">Hero bets</font>, BB calls, UTG+1 folds.

River: (8.25 BB) 8[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">BB bets</font>, Hero ...

BB seems to be a bad player. He is 28/3/2 after about 100 hands.

Do I raise for value here or just call because of scare card. Checking the turn and leading out on the river makes me think he could've been playing an OESD and/or caught the backdoor flush.