AA, 4th suits hits the river

Villain is 38.8/10/.84 w/100 hands. I know MP2 being OOP is pulling the standard Clarkmeister here...

Party Poker 2/4 Hold'em (9 handed) FTR converter on zerodivide.cx

Preflop: Hero is Button with A[img]/images/graemlins/diamond.gif[/img], A[img]/images/graemlins/club.gif[/img].
<font color="#666666">2 folds</font>, MP1 calls, <font color="#CC3333">MP2 raises</font>, <font color="#666666">2 folds</font>, <font color="#CC3333">Hero 3-bets</font>, <font color="#666666">2 folds</font>, MP1 folds, MP2 calls.

Flop: (8.50 SB) 9[img]/images/graemlins/spade.gif[/img], Q[img]/images/graemlins/heart.gif[/img], 7[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
MP2 checks, <font color="#CC3333">Hero bets</font>, MP2 calls.

Turn: (5.25 BB) 2[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
MP2 checks, <font color="#CC3333">Hero bets</font>, MP2 calls.

River: (7.25 BB) 3[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">MP2 bets</font>, Hero??? Do you make the call here? My read is he's betting any spade here with an AF of less than 1.