6. Internal Affairs

The 14th precinct has an informer in its midst. The undercover agents working on a truck hijacking are getting exposed. IAD ""asks"" C&L to investigate, since they're ""outsiders."" When Cagney refuses, the IAD lieutenant smirkily tells her that Charlie was on the take when he was a cop. All they turn up is that LaGuardia has a girlfriend and Samuels is seeing aa psychiatrist because of the effect of his divorce.