KK OOP, min-raised flop and all-in turn

Villain is new to the table, he just came in from the great beyond and posted a blind up front. I have never seen him before.

Party Poker No-Limit Hold'em, $ BB (9 handed) converter

CO ($24)
Button ($25.55)
SB ($28.90)
BB ($10)
Hero ($26.25)
UTG+1 ($6.25)
MP1 ($22.50)
MP2 ($8.05)
MP3 ($18.20)

Preflop: Hero is UTG with K[img]/images/graemlins/club.gif[/img], K[img]/images/graemlins/heart.gif[/img]. CO posts a blind of $0.35. SB posts a blind of $0.10. MP1 posts a blind of $0.25.
<font color="#CC3333">Hero raises to $1.5</font>, <font color="#666666">1 fold</font>, MP1 (poster) calls $1.25, <font color="#666666">6 folds</font>.

Flop: ($3.70) 3[img]/images/graemlins/heart.gif[/img], 4[img]/images/graemlins/diamond.gif[/img], 5[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $2</font>, <font color="#CC3333">MP1 raises to $4</font>, Hero calls $2.

Turn: ($11.70) 7[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, MP1 goes all-in, Hero...?

Final Pot: $11.70

[tagtastic]

Think a while and fold. If he's bluffing there's a good chance he'll show and you'll know there will be plenty more spots that are alot more clear-cut than this to take this guy's stack.

If he doesn't show assume he had it and move on - until he pulls the same move in the next 3 consecutive hands against other opponents, then kick yourself for folding to this maniac as the rest of the table counts their new found wealth.

[beavens]

any reason we're not 3betting this flop?

Beavens,

You would favor 3 betting on the flop, for how much $?