Law & Order (1990) : 17x19

Green and Cassady get mixed up with the Russian consulate after Peter Rostov dies of ricin poisoning. Their investigation leads them first to his work, where they learn he spent a great deal of time traveling back and forth between Russia, and secondly to his brother, Karl. It isn't long before they link the Rostov brothers to an illegal prostitution ring trafficking in young Russian woman, but McCoy is faced with trying to get the remaining Rostov brother to testify so he can prosecute Brezin, the father of one of the trafficked girls.