I think he is not bluffing at this spot. Preflop big blind, and call your raise. With that raise he still got good Odds connected to the Pot with any lower pocketpair (22-99). Then check call Flop and check raise Turn. Just think about the Hands he could have, and if you win against them:
- don't see him having higher pocket pair, he might raises PRF UTG with JJ+.
- AT+ Maybe AQ+ if your villian is a lag but he would never check raise you on the Turn with a hand like that,
So i would fold vs Unknown because you just can win against a small part of his range. Set's are most likely.
I think only stats can help you really out in that situation