AKs from BB, TPTK turns into an ugly 2 pair, call this river?

[RustyCJ]

2nd rotation at the table, no reads, however, this player later turned into a 41/0/.2 after 30 hands - hind sight is 20/20 i know and given his passive style that developed I now feel like the fold was fine, and I figured this is a bet/fold situation.

Party Poker 0.50/1 Hold'em (6 max, 5 handed) FTR converter on zerodivide.cx

Preflop: Hero is BB with K[img]/images/graemlins/club.gif[/img], A[img]/images/graemlins/club.gif[/img].
UTG calls, <font color="#666666">3 folds</font>, <font color="#CC3333">Hero raises</font>, UTG calls.

Flop: (4.50 SB) 7[img]/images/graemlins/club.gif[/img], 5[img]/images/graemlins/spade.gif[/img], A[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, UTG calls.

Turn: (3.25 BB) 3[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, UTG calls.

River: (5.25 BB) K[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, <font color="#CC3333">UTG raises</font>, Hero folds.

Final Pot: 8.25 BB