Paul Kosticky's bluff is broken by Mark's reply

A few players call the big blind, Paul calls from the SB and Mark checks. On the flop we see 8xJx and after Paul checks, Mark bets 700. Everyone folds, and Paul replies.

Turnas Ax and both players check. Riveris 5x and Paul builds 1600. After some thought, Mark answers and points JxTx, and Paul bluffed and reversed 3x6x.