Meet the cast of Line of Duty series four

Nick is the husband of Newton's Roz Huntley and father to the pair's two children.

Where have I seen Lee Ingleby before?

Does Detective Sergeant John Bacchus ring a bell? Ingleby has starred as Martin Shaw's sidekick in seven series of BBC detective drama Inspector George Gently and will appear in one more run before the show is brought to an end after ten years. He is also known for his appearance as Knight Bus conductor Stan Shunpike in Harry Potter and the Prisoner of Azkaba and his role alongside Russell Crowe in Master and Commander: The Far Side of the World. More recently, Ingleby has been seen as the father of autistic child Joe in BBC drama The A Word.

Michael Farmer (played by Scott Reid)

24-year-old Michael Farmer is charged with the murder of two women and the kidnap of another – but did he do it? Or is the known sex offender a convenient suspect taken advantage of by the police? It's down to AC-12 to find out...

Who do I recognise Scott Reid?

Scottish actor Scott has delighted audiences in cult comedy Still Game as Methadone Mick and showed up in TV movie Sketchland. He is currently playing the lead role of Christopher in the UK tour of The Curious Incident of the Dog in the Night-Time.

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DC Jodie Taylor (played by Claudia Jessie)

Young copper Jodie works in Roz Huntley's unit and plays a role in the team's pursuit of Michael.

Why do I recognise Claudia Jessie?

If you're a fan of daytime drama, Claudia played lead Annie Taylor in the third series of WPC 56. She also appears in CBBC web series Dixi as Shari and has showed up in Call the Midwife, Jonathan Strange and Mr Norrell, Doctors and Bull.