The search for what happened to Hayley begins as the team travel down to Middenham to meet her family.
Despite a tragic turn of events, the team narrows down the suspects.
Cassie and Sunny interview two of the suspects again and get closer to the truth.
Cassie and Sunny discover Walsh was chased by all four suspects on the night in question.
Cassie and Sunny interview the four suspects, who all deny knowing the victim.
Cassie and Sunny identify four potential suspects who trained as police officers together....
After making the decision to retire from the police force, Cassie faces a dilemma.
The team race to find evidence to prove the identity of Hayley's killer.
As Cassie and Sunny get closer to the truth, the case takes a devastating turn for Cassie....
Cassie and Sunny suspect the men are lying. The press learn James has been questioned.
Cassie and Sunny interview four men while the team returns to the original investigation.
Cassie and Sunny work to identify human remains found buried near a London motorway.
The most dramatic season yet begs the question: who exactly is fighting for justice?