[DeeJ]

hmm there's all sorts of reasons why villain might not cap the turn but bet the river with KQ if he thought he was up against AJ but the A falls which made AJ more unlikely? Or he wanted to try to get Hero to fold AK whilst he is representing a Jack himself - and also holding 2 pair anyway?

I'd think this is a fairly easy call. Some of the time you're losing to TT. Some of the time you'll chop with AK. Occasionally you'll beat KQ or a bluff. It would certainly be a brave laydown with a big pot like that, and raising seems like spewing given the number of hands you're behind.