Questionable river fold

[Nietzsche]

CO and button are solid TAGs, UTG is a loose passive.

Party Poker 10/20 Hold'em (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

Preflop: Hero is MP with 7[img]/images/graemlins/club.gif[/img], 9[img]/images/graemlins/club.gif[/img].
UTG calls, Hero calls, CO calls, <font color="#CC3333">Button raises</font>, <font color="#666666">1 fold</font>, BB calls, UTG calls, Hero calls, CO calls.

Flop: (10.50 SB) 4[img]/images/graemlins/club.gif[/img], K[img]/images/graemlins/club.gif[/img], J[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(5 players)</font>
BB checks, UTG checks, Hero checks, <font color="#CC3333">CO bets</font>, <font color="#CC3333">Button raises</font>, BB folds, UTG calls, Hero calls, <font color="#CC3333">CO 3-bets</font>, <font color="#CC3333">Button caps</font>, UTG calls, Hero calls, CO calls.

Turn: (13.25 BB) T[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(4 players)</font>
UTG checks, Hero checks, <font color="#CC3333">CO bets</font>, Button calls, UTG calls, <font color="#CC3333">Hero raises</font>, CO calls, Button folds, UTG calls.

River: (20.25 BB) J[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(3 players)</font>
UTG checks, Hero checks, <font color="#CC3333">CO bets</font>, UTG folds, Hero folds.

OK, let me have it.