In exchange for turning a blind eye, Adrian gives Rob the name of someone who knows where Sarah is, but that person turns up dead; believing Sarah may still be alive, David and his team race to her find her.

The detectives suspect a gangland hit when a father and son are shot execution-style in broad daylight, and worry the violence could escalate; David sees an opportunity to finally apprehend crime kingpin Adrian Cook.

While the team looks into the murder of a Portuguese au pair who was recently fired from her job, Vivienne and Rob start investigating David on the sly, but he remains a step ahead of them.

When a boy finds his grandfather dead in a pub basement, he tells Rob that he was hit by a man with a baseball bat, but Vivienne doubts his story; Vivienne pressures Rob to report that he covered for David on the night of Sarah's disappearance.

Construction workers find the remains of a young man who appears to have been strangled to death more than a year ago, but when his sister is notified, she claims he's been sending her postcards all the while.

After a dead woman is found in a river, detectives track the suspect through a dating site only to find he might have shot himself.

Detectives discover a man murdered on his houseboat was having an affair with his best friend's wife.

After a bridegroom is killed at his bachelor party, the crime is reported by the would-be bride's ex-husband.

DC Rob Brady and Trainee DC Billie Fitzgerald respond to a gruesome scene where a man was found stabbed multiple times and left hanging from a tree.

DCI Colin Sutton leads the investigation of a young French woman's slaying in London, which reveals a serial killer is on the prowl.

"Collateral" is a four-part thriller set in London that takes place over four days. When a pizza delivery driver is shot down in South London, Detective Inspector Kip Glaspie, played by "Great Gatsby" star Carey Mulligan, is left in charge of the investigation and refuses to accept the murder as just a random act of violence. As she investigates, she soon finds herself being drawn into the darker side of underworld London. At the same time, politician David Mars, played by John Simm, becomes embroiled in the events due to his rocky relationship with his unpredictable ex, Karen, and a vicar struggles to conceal her affair with the only witness to the shooting. Disparate worlds collide and become entangled as the investigation develops.

Luther is a brilliant but emotionally impulsive detective who is tormented by the dark side of humanity while hunting down murderers. Once the self-destructive detective knows the killer's identity, it becomes a psychological duel between predator and prey.

Based on the best-selling novels by Robert Galbraith (aka J.K. Rowling), Tom Burke ("The Musketeers") stars as private detective Cormoran Strike, a former war veteran now working out of a cramped London office. Together with his assistant, Robin Ellacott, Cormoran tackles cases that have, so far, baffled the police. Though struggling with the psychological and physical toll that combat have wrought on him, Cormoran is well-equipped to delve into complex conundrums thanks to his background as a Special Investigation Branch investigator.

Detectives Rob Reilly and Cassie Maddox find themselves dispatched to investigate the murder of a young girl on the outskirts of Dublin, Ireland. Based on the books "In the Woods" and "The Likeness" by American-Irish writer Tana French, this psychological thriller features a cast of mostly Irish actors, including Killian Scott and Sarah Greene as the leads. The series follows the detectives, who put their friendship to the test, as they are pulled deeper into the intrigue and darkness that surrounds the case.