Law & Order: Criminal Intent (2001) : 5x4

When a cop's son is murdered by the mob, Logan and Barek realise that young Joe Long was killed by mistake, and their investigation leads them to two rival mafia families, but it isn't long before Logan begins to believe that the true criminals aren't the mobsters, but the cops on their payroll. As their investigation narrows down to one main officer, Barek and Logan are faced with the difficult task of having to force the man's daughter to turn against him to get what they want. When the officer and his lawyer bring Logan's stormy history into play, even Deakins takes pause with his decision to have Logan on his force.