Cassie and Sunny go in search of Hayley's family as the press begin to take an interest in the story. A detective who was involved in the original investigation offers his thoughts on why her disappearance remained unsolved, pointing out that Hayley's boyfriend was suspected of the crime but was never charged. The distance between where Hayley was last seen and where her body was found leads Cassie to form a new theory - that the killer may have travelled up from London, then returned before they could be questioned.

The episode was rated 7.73 from 497 votes.

A disturbing allegation about David opens up a second line of enquiry for the team. How much Tessa actually knew about David's life threatens to ruin her relationship with her husband and son. Marion gets into trouble at work and jeopardises her marriage by refusing to open up about her past. After having his phone stolen and information exposed, Colin is blackmailed again - and Sarah's secrets push her family to breaking point.

The episode was rated 7.72 from 614 votes.

Cassie and Sunny identify four potential suspects who trained as police probationers together, and two of them are still serving officers. They have no luck finding the rest of the body and decide to go public about the discovery of Walsh's remains.

The episode was rated 7.72 from 327 votes.

Crime drama series. Detectives Cassie and Sunny begin to find out a bit more about who David Walker was through speaking to his ex-wife Tessa.

The episode was rated 7.70 from 659 votes.

When the body of a teenage girl who went missing at the turn of the millennium is found at a building site off the M1 motorway, four men are placed under the spotlight and their relationships are tested to the limit.

The episode was rated 7.68 from 505 votes.

Detectives Cassie and Sunny reunite as they take on a case concerning the remains of a body found locked in a suitcase in the River Lea. As the pair begin the complicated task of trying to identify the body, the stories of four people with apparent links to the victim begin to unfold. Old wounds are reopened when the detectives track down the victim's wife and son, who have been in the dark about his disappearance for 26 years. Who wanted the man dead and why?

The episode was rated 7.66 from 688 votes.

DCI Cassie Stuart begins to identify the people mentioned in the diary of Jimmy Sullivan.

The episode was rated 7.65 from 679 votes.

As the investigation in to Jimmy's death continues, Cassie and Sunny visit Father Robert Greaves hoping to identify the mysterious Jo-Jo.

The episode was rated 7.64 from 647 votes.

A dismembered body is found in a scrapyard and the team believes the remains had been stored in a domestic freezer for 30 years. Meanwhile, after making the decision to retire from the police force, Cassie faces a dilemma when she learns she isn't entitled to her full pension payment unless she completes her 30 years of service.

The episode was rated 7.61 from 342 votes.

When a skeleton is unearthed, a car key found near the body is the only clue to the identity of the victim.

The episode was rated 7.54 from 758 votes.