Revealed after 20 years: How dentist gassed wife and his lover's husband in their beds... then made it look like a double suicide
30th November 2010
A devout Christian dentist murdered his wife and his lover's policeman husband in a 'devious' and 'professional' manner, a court heard yesterday.
Colin Howell has pleaded guilty to killing his wife Lesley and Constable Trevor Buchanan at their Londonderry homes in 1991 by gassing the pair to give the impression they died in a suicide pact.
Howell's crimes only came to light in January last year when he confessed to his church elders who called in the police after his new life collapsed when he lost more than £350,000 in a scam.
He kept the secret of the murders for almost 20 years before eventually confessing to detectives.
Howell, 51, first killed his wife Lesley and later Constable Buchanan at their homes in Coleraine, County Londonderry, in May 1991 when he attached part of a baby's feeding bottle to a garden hose to poison them with carbon monoxide fumes as they slept.
Howell attached a hose to the exhaust of his Renault Savanna using a baby's bottle he'd cut in in half and then ran the hose through the victims' houses to gas them.
Dentist and lay preacher Howell then drove the pair six miles to the property where they were found, leaving the victims in the car with the door ajar to give the impression that Mr Buchanan had decided against killing himself but was too late.
The court heard yesterday how Howell had then concocted a story to give the impression that his wife and Mr Buchanan had committed suicide because they had struggled to cope after discovering he and Hazel had been having an affair.
A post-mortem examination at the time confirmed both victims had died from carbon monoxide poisoning but a court heard yesterday that Mrs Howell cried out for her son Matthew when she woke up and realised her life was in peril.
Later Howell was involved in a desperate struggle when he gassed Constable Buchanan at his house.
At one stage Howell feared he himself would be overcome by the toxic fumes.
who has pleaded guilty to the murders.
The court heard the two bodies were discovered in Mrs Howell's car in a garage behind a house once owned by her father, who had collapsed and died just days earlier.
Crown lawyer Kieran Murphy told Mr Justice Anthony Hart: 'This was a meticulous and devious plan and pre-meditated in a manner that might be described as professional.'
Howell, now 51, has already been sentenced to life imprisonment after admitting the two murders. He will be told on Friday the minimum term he will have to serve.
His former lover, mother-of-two Hazel Stewart, who remarried after Constable Buchanan's death, has pleaded not guilty to murder and her trial, which is due to begin in early February, is expected to last up to a month.
Howell and Hazel Stewart - then Buchanan - had resumed their affair when the dentist decided to carry out the murders late on the Saturday night of May 18 and the early hours of May 19.
The first was in his own house where his wife, who had been drinking and taking prescription tablets because of her distress over the affair, was sleeping in her night-dress on a sofa.
He used a hosepipe attached to his car exhaust to seep gas into the room where his wife was sleeping but she woke up and cried out for her son Matthew, then aged six, who was with his three siblings aged between nine months and four years.
Howell then pulled a duvet over her head, squeezed hard, and pushed the hose into her face with his right hand and held it there until she died.
The dentist then put his wife's body in the boot of his car and drove across town to kill Constable Buchanan, who was sleeping in the house he shared with Hazel and their two young children, Andrew and Lisa.
Howell had attempted to gas Mr Buchanan with a garden hose but the police officer woke up and looked Howell in the eye before there was a struggle.
In a statement, Howell admitted: 'I pulled the quilt over his head first and with my right hand put the hose to his mouth. I remember him sitting up and I pulled the quilt over him. He saw me.'
Howell then drove to his late father-in-law's empty property in Castlerock where he stage managed the apparent suicides in a small garage.
After donning a pair of plastic surgical gloves, he heaved Mr Buchanan's body from the boot and placed it in the driver's seat and left the door open.
He then laid his wife down in the boot, positioning some family photographs beside her body, and hitting the play button on her personal stereo system after placing the headset over her ears to make it seem she was listening to music.
Howell then connected a length of vacuum hose which had been lying in the car to the exhaust and put the other end into the boot where his dead wife was lying. Before leaving he switched on the ignition.
He benefited by several thousands of pounds from the killings, receiving £212,446 which had been left in his wife's will and gaining £27,000 from the estate of her father worth £27,000.
Insurance against Lesley's death paid out £120,000 and he received £54,635 from an endowment policy.
His dental business began to grow and flourish, having previously been in deficit at the time of the deaths, and in 2008 he sold a home for £131,000.
But then the court heard Howell lost £353,000 on a Philippines scam involving a scheme to recover gold hidden in chambers by the Japanese.
Mr Murphy urged the judge to impose a severe sentence on Howell arguing there were a series of aggravating factors, including the suffering endured by victims' families after believing their loved ones had taken their own lives.
He added: 'The actions of the dentist were calculated, callous, manipulative, evil and wholly without mercy for two defenceless victims, one of whom was his wife and the other the loving husband of his co-accused.'
Howell, a father of ten, was told earlier this month he would be jailed for life with his minimum term to be confirmed on Friday.