Easy laydown or crying call?

[Vammakala]

PokerStars No-Limit Hold'em, $0.50 BB (6 handed) pokerhand.org hand converter

MP ($125.15)
CO ($6.75)
Button ($61.80)
SB ($11.95)
Hero ($50)
UTG ($48.50)

Preflop: Hero is BB with 8[img]/images/graemlins/spade.gif[/img], A[img]/images/graemlins/spade.gif[/img].
<font color="#666666">3 folds</font>, <font color="#CC3333">Button raises to $1.5</font>, <font color="#666666">1 fold</font>, Hero calls $1.

Flop: ($3.25) K[img]/images/graemlins/spade.gif[/img], K[img]/images/graemlins/club.gif[/img], 8[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, Button checks.

Turn: ($3.25) 8[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $2</font>, Button calls $2.

River: ($7.25) 4[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">Button bets $5</font>, Hero ???

The check on the flop was interesting as was the call on the turn. He could've called with an ace high perhaps, but would he bet anything but K on this river?