Osip was seen with Tretiak testing some C-4 in a shipyard. When the Strike Team busted the shipyard later, Tretiak and Osip had left. Vic Mackey sent Ronnie and Lem to capture them and they brought them to one of Tretiak's warehouses. After tying Tretiak to a chair and rigging it with C-4, Mackey started questioning Osip using Irina as a translator. However, Tretiak shook his chair and fell, triggering the C-4 and killing himself. The team fled with Irina and Osip.
While in the van, Osip told them how Tretiak had contacted Antwon Mitchell to kill Officers Wayne Haimes and Carl Miller. He said that Antwon had offered two Nigerian hitmen for the job. He also told them that a third black man was with them at the moment of the deal. When they questioned him about this third man, Osip said that he had brought Tretiak some language tapes before.