Villian is unkown. While i was searching for tables i noticed him on at least 3 of them, with full Bi's on each....so i assume a reg. We still have 2 players 2 act behind....i was lost here....Whats our play?

$0.25/$0.5 No Limit Holdem
6 players
Converted at weaktight.com

Stacks:
UTG Hero ($50.00)
UTG+1 cweezyaf1bb ($66.00)
CO RölliP ($29.70)
BTN lover2000 ($32.90)
SB libecciata ($17.85)
BB Slipp1 ($52.25)

Pre-flop: ($0.75, 6 players) Hero is UTG
Hero raises to $2, cweezyaf1bb calls $2, 1 fold, lover2000 calls $2, 1 fold, Slipp1 calls $1.50

Flop: ($8.25, 4 players)
Slipp1 bets $6.50, hero..