$2/$4 No Limit Hold-em

1 -Evan (10)
2 - Colin (31)
3 - AceintheHole (62)

Evan - On the Button
AceintheHole - SB
Colin -BB
*** HOLE CARDS ***
Dealt to AceintheHole A 9

Evans calls - 4
AceintheHole calls - 2 [4]
Colin raises - 2 [6]
Evan folds
AceintheHole calls 2 [6]

Flop (K K 3 )

AceintheHole bets - $15
Colin calls - $15

I'm trying to make him think I have a king and get him to fold.
He says to me, I think you don't have a king since your trying to buy the pot. I wanted him to fold but he called me.

Turn (K K 3 ) (2 )

AceintheHole checks
Colin - All-in - $10
AceintheHole - All-in - $10

I was already pot commited I thought I had no choice but to stay in.

River (K K 3 2 ) (7 )

Colin shows K K
Colin wins pot with 4 of a kind.

How would you have played this hand differently?
When should have I realized he had at least a King?
Thinking about it right now once he called me ($15) after the flop I should have realized he had a K.
During the time I thought both of us where bluffing but I had a Ace so I stayed in till the end.