Risky Value Bet?

[KingsTown]

Poker Stars - No Limit Hold'em Cash Game - $2/$4 Blinds - 5 Players - (LegoPoker Hand History Converter)

SB: $273.20
BB: $382.40
Hero (UTG): $400.00
CO: $465.00
BTN: $538.00

Preflop: Hero is dealt A[img]/images/graemlins/diamond.gif[/img] K[img]/images/graemlins/diamond.gif[/img] (5 Players)
<font color="red">Hero raises to $16.00</font>, 2 folds, SB calls $14.00, BB calls $12.00

Flop: ($48) 9[img]/images/graemlins/spade.gif[/img] 3[img]/images/graemlins/spade.gif[/img] J[img]/images/graemlins/heart.gif[/img] (3 Players)
SB checks, BB checks, Hero checks

Turn: ($48) A[img]/images/graemlins/club.gif[/img] (3 Players)
SB checks, BB checks, <font color="red">Hero bets $32.00</font>, SB calls $32.00, BB calls $32.00

River: ($144) 7[img]/images/graemlins/diamond.gif[/img] (3 Players)
SB checks, BB checks, <font color="red">Hero bets $72.00</font>, <font color="red">SB raises to $144.00</font>, 2 folds

No reads on either player.