2/4 suspicious push on turn

[Doblame]

Villain has 3-bet my last two raises, to which I've folded. Other than that we haven't had any significant hands. I have him at 28/20 over 110 hands or so.

PokerStars No-Limit Hold'em, $4 BB (4 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

SB ($139.85)
BB ($422.70)
Hero ($470.15)
Button ($675.85)

Preflop: Hero is UTG with J[img]/images/graemlins/club.gif[/img], K[img]/images/graemlins/spade.gif[/img].
<font color="#CC3333">Hero raises to $16</font>, <font color="#CC3333">Button raises to $52</font>, <font color="#666666">2 folds</font>, Hero calls $36.

Flop: ($110) 3[img]/images/graemlins/diamond.gif[/img], 2[img]/images/graemlins/spade.gif[/img], K[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, Button checks.

Turn: ($110) 8[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $72</font>, <font color="#CC3333">Button raises to $623.85</font>, Hero ???.