The team's hunt for the murderer leads them further up the political ladder, and pressure is applied from above as Boyd closes on his quarry despite the government’s secrecy.

A common theme, linking three murders over a 60 year period, is discovered when the case of the murder of an ex-soldier is reopened. Can the team prevent a fourth killing?

The team know what links the victims but they are still searching for the motive - and for the murderer.

An ex-army officer who served in Northern Ireland's Troubles points Boyd's suspicions towards the security services, making the case more complicated than ever. Show more

Mel is suspended from the case pending an inquiry, while Grace and Boyd have more questions for Roper, but the doctor is in no position to answer them.

A woman torches her home, killing her family. She claims that she was incited to commit arson by a mysterious figure called 'The Shepherd'.

Boyd's team are sure the dark figure cited by two homicidal psychiatric patients exists, and continue to investigate the mysterious Shepherd.

A man is admitted to hospital 15 years after he and his twin went missing from their home. Before he can be interviewed, a murder takes place and he goes missing once more.

A man is found dead at a hotel with a word carved into his back, the hallmark of an old crime that the cold case team is already investigating.

Sam Jacobs is released from prison to start a new life. When a man is murdered in his hostel, he becomes a suspect - but he may have been the intended victim.

After Mark’s cousin is murdered, the team establishes Mark’s alibi. Who is the real killer? Drug-running and witness protection muddy the waters.

The secret past of the team's guitar teacher suspect is revealed, and Frankie is embarrassed following the attack on the lab.

The cold case team continues to try to unravel the macabre murders, and DNA evidence brings them towards their suspect.

When the body of a policewoman missing for a year is pulled from the Thames, Boyd and the team discover that she was being followed by two stalkers.

25 years ago, Annie Keel confessed to the murder of her husband and her neighbour’s son. When new evidence calls her confession into doubt, Boyd and the team must dig deeper.

Carl Mackenzie was jailed for a high-street shooting spree but he has always maintained his innocence. Now his sister is fighting for an appeal.

The discovery of a mummified body opens an investigation into a supposedly fictional film from the 1960s.

The team exhume the first victim to find clues with new DNA techniques. When Boyd thinks he is getting closer, he finds he is facing one smokescreen after another. Show more

When someone threatens the surviving victim of the notorious serial killer 'The Gambler', the team must visit the killer himself to discover if he had a partner.

Harry Newman is an old man, dying in a London nursing home. When he makes a deathbed confession of 12 separate 'unauthorised killings', Boyd's team is called in.