Suspected free card play, correct counter?

[Goodnews]

Party Poker 1/2 Hold'em (6 max, 6 handed) converter

CO is 52/7/123

Preflop: Hero is BB with J[img]/images/graemlins/diamond.gif[/img], 8[img]/images/graemlins/heart.gif[/img].
UTG calls, <font color="#666666">1 fold</font>, <font color="#CC3333">CO raises</font>, Button calls, <font color="#666666">1 fold</font>, Hero calls, UTG calls.

Flop: (8.50 SB) 8[img]/images/graemlins/spade.gif[/img], 4[img]/images/graemlins/club.gif[/img], 3[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(4 players)</font>
<font color="#CC3333">Hero bets</font>, UTG calls, <font color="#CC3333">CO raises</font>, Button folds, <font color="#CC3333">Hero 3-bets</font>, UTG folds, CO calls.

I believed I was ahead here and that CO was trying to make a free card play. I watched him do it 4 times on his last 6 flush and open ended straight draws.

Turn: (7.75 BB) 4[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, CO calls.

River: (9.75 BB) 2[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero ???</font>.

Final Pot: 13.75 BB

[jquattro]

This could be a free card play, but more likely the preflop raiser is just raising you because he has overcards or an overpair, or because he thinks you've got [censored]. Value bet river, since it looks more like he had overcards. Call a raise.

[mperich]

Based on your read I like the hand and I check call the river, or bet the river fold to a raise. If he tends to call down with overcards then bet-fold is the best. If he will bet his overcards if you check, then check call is far superior.

-Mike