[rory]

I think I would probably call down. You are getting about 3:1ish on a call down and you might have outs. When someone acts different than they normally do, I want to see what they have for cheap. I wouldn't be surprised if this guy turned over two pair or if he turned over a hand with a straight and a flush draw, something with the Jh or Th in it. So you might be good, you might have outs and worst case you get some valuable information.

The thing making me want to call down is the guy check-raised before when he made his hand. So, we think he might be a check-raiser when he makes his hand so if he is not check-raising here, it is less likely he has two pair.

There are some other considerations-- I assume you have been free carding this passive guy to death. If so, he might be getting sick of that crap and decided to stop-and-go you so you don't get another free card. That would be another reason to call down, because he might be doing the stop and go with a worse hand.

Tough spot-- thanks for the updated read though. Makes analyzing the situation a little easier.