50+5: I have 2 pair. Does he have a set?

[AA suited]

Party Poker No-Limit Hold'em Tourney, Big Blind is t15 (10 handed) converter

saw flop|<font color="#C00000">saw showdown</font>

MP3 (t1000)
CO (t1000)
Button (t1015)
<font color="#C00000">HERO (t985)</font>
<font color="#C00000">BB (t1000)</font>
UTG (t1000)
UTG+1 (t1000)
UTG+2 (t1000)
MP1 (t1000)
MP2 (t1000)

Preflop: HERO is SB with 2[img]/images/graemlins/diamond.gif[/img], T[img]/images/graemlins/club.gif[/img].
UTG calls t15, <font color="#666666">1 fold</font>, UTG+2 calls t15, <font color="#666666">1 fold</font>, MP2 calls t15, <font color="#666666">3 folds</font>, HERO completes, BB checks.

Flop: (t75) 2[img]/images/graemlins/club.gif[/img], T[img]/images/graemlins/diamond.gif[/img], 4[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(5 players)</font>
HERO checks, <font color="#CC3333">BB bets t95</font>, UTG calls t95, UTG+2 folds, MP2 folds, <font color="#CC3333">HERO raises to t300</font>, BB calls t205, UTG folds.

Turn: (t770) 5[img]/images/graemlins/diamond.gif[/img]
HERO ???


Since BB bet out strong, i didnt think he had a set. I put him on top pair.

when he called my 3x check raise, i got concerned. usually on 50+5, a check raise screams overpair or set. but he called it. so i'm thinking he might have a set.

What should be my next move???