50/100 AK vs possible straight and flush

20 hands on the villian, so he is basically unknown but seems tight so far. This is the first time I've seen him cold call pf, I haven't seen him go to showdown yet. This is probably boring and standard, but I want to make sure. Button in the hand sucks and is loose.

50/100 Hold'em <font color="#0000FF">(10 handed)</font>

Preflop: Hero is UTG with A[img]/images/graemlins/diamond.gif[/img], K[img]/images/graemlins/heart.gif[/img].
<font color="#CC3333">Hero raises</font>, <font color="#666666">5 folds</font>, CO calls, Button calls, SB calls, <font color="#666666">1 folds</font>.

Flop: (9.00 SB) A[img]/images/graemlins/spade.gif[/img], Q[img]/images/graemlins/diamond.gif[/img], 2[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(4 players)</font>
SB checks, <font color="#CC3333">Hero bets</font>, <font color="#CC3333">CO raises</font>, Button folds, SB folds, <font color="#CC3333">Hero 3-bets</font>, CO calls.

Turn: (7.50 BB) K[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, <font color="#CC3333">CO raises</font>, Hero calls.

River: (11.50 BB) 8[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
Hero ???