Benjamin Fitton - They Walk Among Us: A Chilling Casebook of Horrifying Hometown Crimes

Benjamin and Rosanna Fitton are the husband and wife team behind the number one hit podcast They Walk Among Us. The podcast started in September 2016, focusing on crime in the UK. Delving into the crimes that are close to home, the criminal that sleeps beside you, lives next door, or delivers your newspaper. The podcast has won two British podcast awards for best true crime podcast and a Lovie Award for best entertainment podcast.

Benjamin and Rosanna live together with their five cats in Northamptonshire.

When two dead bodies were discovered inside a garaged car in May 1991, it seemed like a suicide pact by two desperate people made miserable by ongoing adultery.

The woman, Lesley Howell, was clutching photographs of her family.

The man, Trevor Buchanan, was a scenes of crime officer with the Royal Ulster Constabulary. Both were unwillingly linked by a love affair involving their partners that was well-known in the compact community of Coleraine, Northern Ireland, that they all called home.

But little at the scene made sense why were some of the photo frames grasped by Lesley Howell facing the wrong way and why were her shoes askew? Would she really have chosen to end her life on the second birthday of a beloved son? The vacuum hose that seemed to funnel exhaust fumes into the car was a puzzlingly loose fit.

Facial injuries marked Trevor Buchanan and both victims had traces of drugs in their systems. And wasnt it strange that two people intent on ending their lives were not sitting side-by-side in the front of the car? Lesley Howell was sprawled in the boot while Trevor Buchanan was awkwardly half inside the drivers seat with the window open, as if he had changed his mind and tried to leave the vehicle, but not in time.

No fingerprints were taken from the framed photographs or a cassette player in Lesleys possession set up to play her favourite gospel music. Forensic investigation was kept to a minimum and no scene log, sketches or measurements were made.

Police accepted the version of events leading up to the deaths from Lesleys dentist husband Colin, and Trevors wife Hazel, without undue scrutiny. The pair needed to say little to persuade investigators of the suicide theory.

Colin Howell was an educated and professional man, who exuded a credible confidence. Furthermore, he was a devout Baptist. Outwardly, his lover, Hazel Buchanan, bore all the hallmarks of a grieving widow. As another committed member of the church she also seemed above suspicion.

At the time police had no way of knowing who Colin Howell truly was or that he would later admit to drugging some of his female patients when they came to his surgery for dental work before sexually assaulting them when they were under the influence of the medication he administered.

At best, the extended families were left bereft at the bleak and untimely ending that their loved ones had apparently chosen. At worst, casual gossip cast the dead pair themselves as illicit lovers.

Crucially, information given to the police at the time by a witness who said Howell was drugging his wife, had cash difficulties and had even tried to kill Lesley previously wasnt acted upon.

Two decades later, Police Ombudsman Nuala OLoan called the original Royal Ulster Constabulary probe deeply flawed and lacking objectivity, subsequently letting down the families of both victims. The improbable position of the bodies alone should have been a lightbulb moment, she said.

But all this only unfolded after a startling confession by Howell in which he admitted the double killing. If he hadnt done so, in a belated fit of remorse, the dentist and his lover would have undoubtedly got away with murder.

This case begins many years before Lesley Howell and Thomas Buchanan lost their lives. A brief outline of the commonplace backgrounds of those responsible offers no clue to what lay ahead.

Colin Howell, the fourth of five children in a Protestant family in Belfast, was not academically gifted but hard work gained him a place at Queens University in Belfast where he studied dentistry.

While he was studying, he met Lesley Clarke, his future wife and victim. She was a student nurse at the Royal Victoria Hospital in the city. She had been born in England to Northern Irish parents and lived in Scotland and Dublin before arriving in Belfast.

Howell was reserved, devout and an awkward outsider in the typically fun-loving student lifestyle. Lesley was affable, warm-hearted and kind. They shared a faith, although Lesleys approach to it was more discreet, her life experience having been broader.

During their courtship the pair had no fewer than three secret abortions in London, with two coming in the space of seven months. This wasnt something Howell wanted to admit to, given his ostentatious faith. Of course, despite more liberal laws elsewhere in the UK, abortion was and still is illegal in Northern Ireland. The couple married in July 1983, with their first son, Matthew, arriving the following year.

Afterwards, Howells career appeared to be on the ascent. Lesley stayed at home raising their new child but missed the fulfilment of nursing, finding home-making a poor replacement for the buzz of a vocation. She became pregnant a second time, tragically losing her mother ten weeks before their daughter, Lauren, was born in November 1986. Her spirits were low. As with numerous other couples, the hard realities of being married with children started making themselves felt.

Lesley struggled as a stay-at-home parent, taking care of two small children. Howell built up unfeasibly large debts as he invested in a new dentistry practice and a bigger home. Yet a working wife who might have helped to make ends meet would have offended his dogmatic belief in domestic orthodoxy. His response to feeling under pressure at home and at work was to have a casual affair with a married woman, something which devastated Lesley.

Although the marital relationship was unravelling fast, both put on a smile that masked the turmoil, particularly when it came to attending services at Coleraine Baptist Church. The church was central to their existence.

Howell, who aspired to be a significant figure in church life, had accepted several roles there, appearing every inch an upright God-fearing citizen. Yet behind closed doors he was a different man. Although theres no evidence he raised a hand to his wife, his actions were having an impact on Lesley. If the early warning signs of emotional abuse had been more easily recognised back then, those around her might have identified what was happening.

More children arrived and the marriage might have limped on for many more years had it not been for Howells next extra-marital fling with a woman from the same congregation.

Hazel Buchanan was a Sunday school teacher, devout, and always well turned out. A farmers daughter, she had been married to her husband, Trevor, since 1981 and they had a daughter, Lisa, and son, Andrew. She was a devoted mother and kept an immaculate house.

Trevor actively embraced his wifes faith. One of four brothers in the same family to join the police force, he was a well-liked family man.