[Diplomat]

I agree. If he has a boat on the turn he's betting hoping to be checkraised or to make you pay for your draw, drawing dead. I can't think of a single legit reason he might check the turn...maybe if he thinks you have the ace-high draw, thinks you will bluff the river, and thinks you will call a raise on the river (but will not call a river bet?). I'm tired though and could be wrong.

-Diplomat