Tough river decision against unknown

[Verdi]

I don't like how I played this one. Thoughts?

Paradise Poker No-Limit Hold'em, $0.25 BB (10 handed) converter

Hero ($62.50)
MP1 ($20.25)
MP2 ($46.00)
MP3 ($39.00)
CO ($19.25)
Button ($45.50)
SB ($23.75)
BB ($16.75)
UTG ($20.50)
UTG+1 ($28.25)

Preflop: Hero is UTG+2 with Q[img]/images/graemlins/club.gif[/img], K[img]/images/graemlins/diamond.gif[/img]. SB posts a blind of $0.25.
<font color="#666666">1 fold</font>, UTG+1 calls $0.50, Hero calls $0.50, <font color="#666666">1 fold</font>, <font color="#CC3333">MP2 raises to $1</font>, MP3 calls $1, <font color="#666666">1 fold</font>, Button calls $1, <font color="#666666">1 fold</font>, BB calls $0.50, UTG+1 calls $0.50, Hero calls $0.50.

Flop: ($6.25) K[img]/images/graemlins/club.gif[/img], K[img]/images/graemlins/heart.gif[/img], 4[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(6 players)</font>
BB checks, UTG+1 checks, <font color="#CC3333">Hero bets $3</font>, MP2 calls $3, MP3 folds, Button folds, BB folds, UTG+1 folds.

Turn: ($12.25) 8[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $5</font>, <font color="#CC3333">MP2 raises to $10</font>, Hero calls $5.

River: ($32.25) 6[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">MP2 bets $32</font>, Hero calls $32.

Final Pot: $96.25

Results to follow.