Breck Bednar was a popular boy who loved online gaming. He was a member of the Air Training Corps and attended church every week with his family. But when he met deviant predator Lewis Daynes online, his personality changed. It was a friendship that would have cruel and tragic consequences.

Thomas and Lisa Infante had four children and a volatile marriage. One day, Lisa announced she'd had enough, she'd met someone else, and she wanted out. As divorce proceedings began, Lisa prepared for her new life by getting fit and stockpiling cash. Thomas was devastated, and one night an argument became a murder.

Back-to-school killer Jesse Matthew preyed on young students finding their feet at university. After getting away with a string of campus sex attacks, he took his depravity to the extreme when he began abducting and murdering young, vulnerable women. These were horrendous crimes that went unpunished for years.

Local politician Stephen Searle had a dirty secret; he was sleeping with his son's girlfriend, the mother of his grandchild. When his wife Anne found out she was devastated, humiliated, bitterly angry. After weeks of alcohol-fuelled fights and recriminations Searle and his wife clashed for one final time.

Pilot Iain Lawrence put his wife Sally on a pedestal, until he lost his job. After that, her position as a successful businesswoman was a reminder of the failure he'd become. When their marriage fell apart he refused to accept the loss of not only his wife, but the wealth and status he had grown accustomed to.

In the Summer of 2014, a drink thrown in a Manchester nightclub triggered a gangland feud that caused years of ruthless violence. Mark Fellows, nicknamed The Iceman, executed two of his rivals in cold blood. Afraid, witnesses refused to give evidence against him until his passion for running became his downfall.

Ann Marie Anastasi and her husband Anthony had an atypical domestic arrangement that they both enjoyed: a younger woman, Jacqueline Riggs, shared their bed and lived in their basement. But then, Anthony chose the 25-year-old over his wife of two decades, and Ann Marie vowed to punish them both.

As mid-life crises go, millionaire Peter Morgan's was spectacular. He slept with dozens of escorts, eventually setting one, Georgina Symonds, up in a house, paying thousands a month for the pleasure of her company. When he discovered she was plotting to blackmail him, he hatched a plan to keep her quiet.

Lea Adri-Soejoko and Rahim Mohammadi were very different people, brought together by their shared love of gardening. Refugee Mohammadi's allotment was a mark of acceptance into British society, which is why he would do anything to keep it. Even kill his mentor, kindly 80-year-old allotment society secretary, Lea.

Philip Nicholson wanted a normal life with things like independence, a girlfriend, and a family of his own, like the happy home of his childhood. He thought he'd found all that with Isabella Gossling, but she had other ideas. Along with predatory bully Richard Moors, they started a game that would end in Philip's death.