Suspicious line from UTG limpers...is it weak to fold this?

[Scorpion Man]

I was very suspicious of the action from the beginning. Villain plays 25/4.4/1/7
I had a note that he c/r the turn with the nuts in a previous session...
I know that checking behind on this flop is not conventional...i was interested in pot control and wanted to see if he bet out. I understand I may have induced a bluff here.

Party Poker
No Limit Holdem Ring game
Blinds: $3/$6
9 players
Converter

Pre-flop: (9 players) Hero is UTG+1 with A[img]/images/graemlins/spade.gif[/img] Q[img]/images/graemlins/heart.gif[/img]
UTG calls, <font color="#cc0000">Hero raises to $20</font>, 7 folds, UTG calls.

Flop: 5[img]/images/graemlins/diamond.gif[/img] 7[img]/images/graemlins/club.gif[/img] Q[img]/images/graemlins/diamond.gif[/img] ($49, 2 players)
UTG checks, Hero checks.

Turn: 3[img]/images/graemlins/spade.gif[/img] ($49, 2 players)
UTG checks, <font color="#cc0000">Hero bets $30</font>, <font color="#cc0000">UTG raises to $85</font>, Hero calls.

River: 7[img]/images/graemlins/spade.gif[/img] ($219, 2 players)
<font color="#cc0000">UTG bets $150</font>, Hero ???

[Go_Blue88]

as played I call the river for sure. no way he has you on AQ.

i don't really get your reasoning for not CB'ing...

[Praetor]

Bet the flop yo