ITV Revisits Notorious Howell Stewart Murder Case

On the night of May 19, 1991, tragedy struck in Castlerock, County Londonderry, Northern Ireland. The bodies of Lesley Howell, 31, and Trevor Buchanan, 32, were discovered in a car parked in the garage of Mrs. Howell’s father, who had himself passed away only weeks earlier. The circumstances were as haunting as they were mysterious: Trevor was slumped in the front driver’s seat, while Lesley lay in the boot of the car, headphones on her ears and family photographs placed tenderly beside her. A vacuum cleaner hose attached to the car’s exhaust pipe snaked into the boot near Lesley’s head, pointing unmistakably to carbon monoxide poisoning.

At first, the deaths appeared to be a heartbreaking joint suicide. The community mourned, and the families of both Hazel Stewart and Colin Howell—spouses of the deceased—were left shattered. But as it turned out, nothing about that night was as it seemed.

It would take almost two decades for the real story to come to light—a story that would grip Northern Ireland and, years later, captivate television audiences across the UK. In 2009, Colin Howell, a respected dentist, confessed to his role in the murders, implicating his former lover, Hazel Stewart, in the process. According to legal documents cited by ITV and the Irish Independent, Howell’s confession came after he lost £353,000 in a bizarre gold bullion scam in the Philippines, and after he admitted to another affair and to indecently assaulting women at his dental clinic in Ballymoney, County Antrim.

Howell’s confession shattered the carefully constructed narrative that had fooled police and family for so long. He and Hazel Stewart, once a Sunday school teacher, had been having an affair. The deaths of their partners, Lesley and Trevor, were not a tragic suicide pact but a calculated double murder, meticulously staged to look like one.

During the 2011 trial, Howell painted a vivid picture of their relationship. "Hazel and I were waltzing together, in time. All the side-stepping was done together. I was not dragging her around the floor. I may have been the lead partner in that dance, but she was doing it in perfect harmony, and willingly," he testified, according to court records reported by ITV. The prosecution argued that Stewart was not a passive participant but a willing accomplice, a claim that would be supported by her own words during police interviews.

Legal documents detail a pivotal moment: in her fourteenth police interview, Stewart was confronted with the suggestion that she knew Howell was coming to murder her husband and that she had been part of the plan from the beginning. When asked, "You fully accept that?" Stewart replied, "Yes, I do." This admission stood in stark contrast to her earlier denials of involvement or knowledge of the plan. When pressed further—"You were allowing somebody with your consent (and you had been in it from the start) to come and murder your husband, that he had murdered his own partner which was all part of the plan? Do you accept that?"—she answered, "Yes."

The trial revealed chilling details about the aftermath of the murders. Stewart helped Howell cut up and burn the garden hose used to deliver the fatal fumes, washed the bedclothes, and agreed to concoct a false story that successfully misled investigators for years. The elaborate cover-up would ultimately unravel with Howell’s confession, but not before it had inflicted lasting pain on the families of the victims.

Hazel Stewart was convicted in 2011 of the murders of Lesley Howell and Trevor Buchanan and sentenced to 18 years in prison. She is currently serving her sentence in HMP Maghaberry, a high-security prison near Lisburn, Northern Ireland. In 2025, Stewart sought to overturn her conviction, claiming she had been suffering from severe PTSD and depression at the time of the murders. However, her appeal failed, and the original sentence stood.

The impact of these crimes has been profound, particularly for the children of Lesley Howell. For years, they grew up under the care of their father, Colin Howell, believing the devastating lie that their mother had taken her own life. The truth, when it finally emerged, was even more difficult to bear. Speaking in response to Stewart’s failed appeal, Lesley’s children expressed the enduring pain caused by the murders and Stewart’s continued attempts to evade justice. "This is a life sentence, and we must continue to live with the pain caused by Hazel's ongoing attempt to evade justice. Nothing will bring our mum back [...] [Our] beautiful mum's memory will not be shadowed by this, and we will continue to love and honour the person she was."

The story of Lesley Howell and Trevor Buchanan’s murders has fascinated and horrified the public for decades. It has been the subject of documentaries, dramatizations, and, most recently, a new examination by ITV as part of its Killer in the House series. On January 27, 2026, ITV1 aired Killer in the House: The Murders of Lesley Howell and Trevor Buchanan, a documentary that delves into the details of the crime more than thirty years after it occurred. For the first time, the program included interviews with the Howell children, offering a deeply personal perspective on the tragedy and the years of deception that followed.

According to The Guardian, the documentary is just one part of a broader television landscape increasingly interested in true crime and the complexities behind notorious cases. The program sits alongside other crime-focused shows, reflecting a public appetite for stories that challenge assumptions and reveal hidden truths. What sets this documentary apart, however, is its willingness to confront the lingering shadows cast by the crimes and to give voice to those most affected.

As the documentary makes clear, the truth about the murders is still emerging, even decades later. The case has prompted difficult questions about trust, justice, and the human capacity for deception. It’s a story that refuses to fade quietly into history, not least because of the ongoing pain experienced by the families left behind.

While Hazel Stewart remains incarcerated, the wounds inflicted by her actions—and those of Colin Howell—are far from healed. For the families of Lesley Howell and Trevor Buchanan, the search for closure continues. Yet, as Lesley’s children have made clear, their mother’s memory will not be defined by the darkness of her final moments, but by the love and strength she showed in life. Their determination to honor her legacy stands as a quiet testament to resilience in the face of unimaginable loss.