3/6 Party -- AK oop -- should I have fired again on turn?

[srjunkacct]

No stats on Villain. He's been at the table for 4-5 orbits, hasn't played too many hands and hasn't done anything too provocative yet. Comments on all streets appreciated.

Party Poker ($3/$6 limit). Hand converted by Check Raised hand converter

Preflop (8 players): Hero is SB with
HERO posts small blind.
BB posts big blind.
[seat8] calls [2.33:1].
UTG+1 folds [2.33:1].
MP1 folds [2.33:1].
MP2 folds [2.33:1].
CO folds [2.33:1].
BTN folds [2.33:1].
HERO 2 bets.
BB calls [5:1].
[seat8] calls [6:1].

Flop (6 small bets ($18) in pot, 3 players):

HERO bets.
BB folds [7:1].
[seat8] calls [8:1].

Turn (4 bets ($24) in pot, 2 players):

HERO checks.
[seat8] bets.
HERO calls [6:1].

River (6 bets ($36) in pot, 2 players):

HERO checks.
[seat8] bets.
HERO ??? [7:1].