10/20 6max: confusing action - river fold? ATo

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Villain is a 37/28/2.7 over 40 hands.

Party Poker 10/20 Hold'em (6 max, 5 handed) converter

Preflop: Hero is BB with T[img]/images/graemlins/diamond.gif[/img], A[img]/images/graemlins/club.gif[/img].
<font color="#666666">1 fold</font>, <font color="#CC3333">MP raises</font>, <font color="#666666">2 folds</font>, Hero calls.

Flop: (4.50 SB) 2[img]/images/graemlins/spade.gif[/img], K[img]/images/graemlins/club.gif[/img], 9[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">MP bets</font>, Hero calls.

Turn: (3.25 BB) T[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, MP checks.

River: (3.25 BB) 7[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, <font color="#CC3333">MP raises</font>, Hero calls.

Final Pot: 7.25 BB

I called the flop as there's a good chance I'm ahead, and I've taken a more showdown-oriented approach lately to dealing with the LAGs. Should I check the river to induce a bluff? The check-through looked like a cheap-showdown move, I thought he'd call with A-high expecting me to bluff at the pot. The raise has me confused but I figured that there's greater than a 1 in 6 chance he'd do this with a 7 that he just hit, A7 etc, maybe even as a pure bluff.

Surf