Is there a man alive who bets this river?

[Redmen62]

Party Poker 1/2 Hold'em (10 handed) converter

Preflop: Hero is SB with A[img]/images/graemlins/heart.gif[/img], A[img]/images/graemlins/club.gif[/img]. CO posts a blind of $1.
UTG folds, UTG+1 calls, <font color="CC3333">UTG+2 raises</font>, MP1 folds, MP2 calls, MP3 folds, CO (poster) calls, Button calls, <font color="CC3333">Hero 3-bets</font>, BB calls, UTG+1 calls, UTG+2 calls, MP2 calls, CO calls, Button calls.

Flop: (21 SB) K[img]/images/graemlins/heart.gif[/img], K[img]/images/graemlins/spade.gif[/img], 5[img]/images/graemlins/spade.gif[/img] <font color="blue">(7 players)</font>
<font color="CC3333">Hero bets</font>, BB folds, UTG+1 folds, <font color="CC3333">UTG+2 raises</font>, MP2 calls, CO folds, Button calls, Hero calls.

Turn: (14.50 BB) J[img]/images/graemlins/spade.gif[/img] <font color="blue">(4 players)</font>
Hero checks, UTG+2 checks, <font color="CC3333">MP2 bets</font>, Button calls, Hero calls, UTG+2 folds.

River: (17.50 BB) J[img]/images/graemlins/diamond.gif[/img] <font color="blue">(3 players)</font>
Hero checks, MP2 checks, Button checks.

Final Pot: 17.50 BB
<font color="green">Main Pot: 17.50 BB, between Button, Hero and MP2.</font> &gt; <font color="white">Pot won by Hero (17.50 BB).</font>

Results in white below: <font color="white">
Hero shows Ah Ac (two pair, aces and kings).
MP2 shows Ad 8s (two pair, kings and jacks).
Button shows 4s 4h (two pair, kings and jacks).
Outcome: Hero wins 17.50 BB. </font>

Anyone bet out on this river, or the turn for that matter? I very, very nearly folded on the turn. Can betting out possibly be +EV here? If there was a bet on the river, is it a clear call? Comments on all streets appreciated.