100nl 6m flush, villain pushes river

[maddoc]

Villain is unknown. I sat dawn a few rounds ago.

Poker Room skin
No Limit Holdem Ring game
Blinds: $0.50/$1
5 players
Converter

Stack sizes:
UTG: $126.10
CO: $68.10
Hero: $125.20
SB: $103.75
BB: $116.20

Pre-flop: (5 players) Hero is Button with T[img]/images/graemlins/spade.gif[/img] A[img]/images/graemlins/club.gif[/img]
UTG calls, CO folds, <font color="#cc0000">Hero raises to $5</font>, 2 folds, UTG calls.

Flop: A[img]/images/graemlins/spade.gif[/img] K[img]/images/graemlins/spade.gif[/img] J[img]/images/graemlins/spade.gif[/img] ($11.5, 2 players)
UTG checks, Hero checks.

Turn: 3[img]/images/graemlins/spade.gif[/img] ($11.5, 2 players)
UTG checks, <font color="#cc0000">Hero bets $10</font>, <font color="#cc0000">UTG raises to $30</font>, Hero calls.

River: A[img]/images/graemlins/heart.gif[/img] ($71.5, 2 players)
<font color="#cc0000">UTG is all-in $91.1</font>, Hero???

Limp/call PF means PP,SC,Axs, may be QsJ. How often villain bluff here? Easy call or heroic fold?