This hand left me all confused. He says he had AK, but there's no reason to believe him since he limped. Should I have led out the turn with a bet to see where I was at and to protect from a bluff? Any comments appreciated.....

Hand #4215836-29 at SnG-0009o (No Limit Hold'em Sit and Go)
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Started at 30/Jan/05 16:58:07

pairof4s is at seat 1 with 930.
jstosh is at seat 2 with 530.
squidly1 is at seat 3 with 1710.
grunnymoney is at seat 4 with 1080.
foldem up is at seat 5 with 1655.
flyingcatfish is at seat 6 with 1210.
river815 is at seat 8 with 2010.
Senfan is at seat 9 with 875.
The button is at seat 6.

river815 posts the small blind of 20.
Senfan posts the big blind of 40.

pairof4s: -- --
jstosh: -- --
squidly1: -- --
grunnymoney: Ah 4h
foldem up: -- --
flyingcatfish: -- --
river815: -- --
Senfan: -- --

Pre-flop:

pairof4s folds. jstosh folds. squidly1 folds.
grunnymoney calls. foldem up folds. flyingcatfish
calls. river815 calls. Senfan checks.

Flop (board: 6c As 4s):

river815 bets 40. Senfan calls. grunnymoney raises
to 185. flyingcatfish calls. river815 folds.
Senfan folds.

Turn (board: 6c As 4s 3s):

grunnymoney checks. flyingcatfish goes all-in for
985. grunnymoney folds. flyingcatfish is returned
985 (uncalled).