Hit my 2 outer for trips on 4th street, how to make the most profit?

I bet, bet here. I am thinking I should have check/called 4th street, then check/raised 5th street. Is there a chance he may take a freecard on 4th street if I checked if he had a heart?

The CO is a decent player but I have seen him showdown less than premium hands before. I knew he had a strong hand preflop when he caped though.

Party Poker 2/4 Hold'em (9 handed) converter

Preflop: Hero is SB with Q[img]/images/graemlins/club.gif[/img], Q[img]/images/graemlins/diamond.gif[/img].
<font color="#666666">1 fold</font>, UTG+1 calls, <font color="#666666">3 folds</font>, <font color="#CC3333">CO raises</font>, <font color="#666666">1 fold</font>, <font color="#CC3333">Hero 3-bets</font>, <font color="#666666">1 fold</font>, UTG+1 folds, <font color="#CC3333">CO caps</font>, Hero calls.

Flop: (10 SB) 7[img]/images/graemlins/club.gif[/img], 9[img]/images/graemlins/heart.gif[/img], 6[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">CO bets</font>, Hero calls.

Turn: (6 BB) Q[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, CO calls.

River: (8 BB) 4[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, CO calls.

Final Pot: 10 BB