No real read here on about the 2nd orbit at the table villian hasnt done anything to stand out in my mind yet.

I am about am maybe 60% sure this is a stone cold bluff if I am last to act after this guy I am raising here usually but with 2 other guys behind me I didnt here. Should I still have tried to pick off his bluff?

Party Poker No-Limit Hold'em, $ BB (10 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

MP2 ($23.35)
MP3 ($20.85)
CO ($23.10)
Button ($22.75)
Hero ($25.60)
BB ($29.02)
UTG ($43.05)
UTG+1 ($24.15)
UTG+2 ($24.80)
MP1 ($31.55)

Preflop: Hero is SB with A, K. Hero posts a blind of $0.10.
UTG calls $0.25, 2 folds, MP1 calls $0.25, 2 folds, CO raises to $1, 1 fold, Hero (poster) calls $0.90, 1 fold, UTG calls $0.75, MP1 calls $0.75.

Flop: ($4.25) 7, 5, 8 (4 players)
Hero checks, UTG checks, MP1 checks, CO bets $3, Hero folds, UTG folds, MP1 folds.

Final Pot: $7.25