Gibbs, the unwilling accomplice

Agent Gibbs from NCIS was somehow caught up with these people who were forcing him to go into a little room where people were chained up and whip them with a chain. When he is back with his crew, he subtly (for some reason) drops a hint at what is going on by accidentally dropping a few bits of the whipping chain he was using. At first his fellow agents are reluctant to believe what the evidence is telling them, but eventually they (and I) find the place and break it up.