S04E20 — Faith

When Ali's testimony results in the release of a killer (Dean Bulmer), Coscorella takes it too seriously and makes catching Bulmer his sole goal, much to the displeasure of homicide detective Len Harper. Nicco is furious with Ali and believes she should have lied to keep Bulmer in jail, and tries desperately to keep the father of one of the victims from taking justice into his own hands. Cold squad is in danger of being closed down, and the officers absorbed into the homicide division.