[tizim]

Here are some things to consider:

1) CO raise/called the flop, then just called the turn, so unless he slowplayed the turn with a flush, he must have a hand that was made on the flop that he wants to showdown (i.e. Ax, 33). If that's the case, he's less inclined to bluff the river because people usually don't bluff with showdownable hands last to act (think checking behind the river with A-high).

2) If you call the river, MP1 will be hard-pressed to overcall with AJ/JJ, so you don't really have to worry about him. It's almost like you're bluff-calling vs him.

Despite (1), I probably call this river because CO's stats suggest he doesn't really know what he's doing, and I think you'll catch him bluffing 1 in 14 times.