[DiceyPlay]

The only reasonable draw he could be on is a flush draw and he's got plenty of overlay to call through the turn.

If he's not on a draw, he's got a K with a worse kicker and he's calling you down. But since you raised pre-flop, this seems less likely.

He makes a mistake by not betting this river unless he strongly believes you'll bet it. I would have checked the river in your spot unless I had some other read on my opponent. If the flop had been more coordinated, I'd be more inclined to bet the river. But I don't see what other hand he would have. However, his check on the river might induce a value bet from me.

If the table isn't loose-passive I muck A4s in mp2 pf after two limpers.