Bobby Nish

The murder of a gang member in Oakland forces Cho to confront his murky past. It emerges that the victim was an old friend of Cho's - and he is willing to go to extreme lengths to exact revenge.

Poisoning is suspected as the team probes the murder of a male stripper found dead in the wake of a female sex party, and a deep-sea diver is fatally stabbed while underwater.

The team searches for Jack's friend Max Cassidy, a longtime FBI agent who disappears after leaving an emotional message on his wife's answering machine about the murder of his partner, Jimmy Haggerty. The squad investigates whether the industrial espionage case that Max and Jimmy were working on is connected to Jimmy's murder and if Max is now a victim of Jimmy's killer.