Detective Lydia Adams
Regina King

Smart and perceptive, Detective Lydia Adams possesses excellent investigative instincts. Working in the homicide division, she is one of the sharpest detectives around. But, perhaps because of her great skill as a detective, Lydia has difficulty in her personal life. Lydia has burned through numerous professional partners over the past few years and is unable to find a healthy romantic relationship. Lydia is extremely guarded and independent to the point of being stubborn. This season, however, as Lydia struggles with the brutality of single motherhood, she begins to realize that she can’t just “do it alone”. As her partner Ruben Robinson (guest star Dorian Missick) matures in the job, he challenges her both personally and professionally, forcing Lydia to evolve into something more than just a great detective.

Officer Sammy Bryant
Shawn Hatosy

Sammy Bryant is a former gang detective who returned to patrol after the brutal murder of his partner, in the hopes of teaching rookie cops how to survive on the streets. He rides with Officer Ben Sherman, though it is becoming increasingly clear that while they wear the same uniform, it is cut from a different cloth. Sammy is a genuinely altruistic and honest man sometimes to his own detriment. Sammy is entangled in an ugly and expensive custody battle with his unstable ex-wife Tammi (guest star Emily Bergel) over their 2-year-old son Nate, who is the most important thing in the world to Sammy.

Officer John Cooper
Michael Cudlitz

Officer John Cooper is a seasoned patrol cop, blue to the bone, and Ben Sherman’s former Training Officer. Back pain from various work-related injuries caused John to become addicted to painkillers, eventually forcing Ben to check him into rehab. Surgery on his back put him on the road to recovery, but his emotional wounds and chronic loneliness have not been so quick to heal. John spent last season riding with Officer Jessica Tang (special guest star Lucy Liu), who was monitoring his fitness for duty. This season, we find him once again training “boots” – but his current charge, Gary Steele (guest star Derek Ray), an ex-marine, challenges John, causing him to examine his identity and ask the question: what happens after you hang up the uniform?

Officer Ben Sherman
Ben McKenzie

Officer Ben Sherman is a patrol officer whose handsome face and Beverly Hills upbringing make him a target of ridicule among his fellow officers, but Ben is out to prove than he is much more than just a “poster boy” – though he does enjoy the attention. Having completed his training rotation with Officer John Cooper, Ben is currently partnered with Officer Sammy Bryant. While he has moved on to the next phase of his police training, Ben’s short fuse still lands him in trouble and shows his naïveté. This season more than ever, we begin to see how the streets of Los Angeles will define the man Ben Sherman will become.

Dewey Dudek
C. Thomas Howell

A veteran cop, as seasoned as the asphalt of the streets he patrols, Dewey Dudek is outspoken to say the least and his smart-aleck attitude often makes him the source of conflict with both civilians and fellow officers. Dewey is a recovering alcoholic, but beneath his coarse exterior and extensive resume of screw-ups is a great cop with a good heart. Dewey is married with two daughters and is one of Officer John Cooper’s only friends.

Officer Henry “Hank” Lucero
Guest Star Anthony Ruivivar

Henry “Hank” Lucero is an experienced patrol cop and Officer John Cooper’s new partner. Born and raised in East L.A., Lucero speaks the language of the streets and believes that “99% of the job is comedy.”  Lucero is a Chicano but he insists that he is “blue not brown” and refuses to speak Spanish to Hispanic suspects, or grant them any special treatment. In Lucero, Cooper has finally found an equal and maybe, even a friend.

Detective Ruben Robinson
Guest Star Dorian Missick

Ruben Robinson is Detective Lydia Adams’ partner. Having started as a trainee under Lydia, Ruben has now found his footing as a detective. While he and Lydia are great friends, he is no longer afraid to challenge her on the job. A native Angelino, ex-Marine and family man with a wife and three kids, Ruben doesn’t define courage as facing danger and overcoming it – but getting up the next day and doing it all over again. His strong core beliefs in family, honor and loyalty define his actions and sometimes create conflict with Lydia.

Character bios from TNT.