A murderous grandfather who gunned down his daughter’s ex-lover and his father in a custody row has been sentenced to life.
Widower Stephen Alderton, 67, will serve a minimum of 25 years behind bars for the double murder of father and son Gary, 57, and Joshua Dunmore, 32.
Alderton went on a ruthless killing spree on March 29, repeatedly blasting the Dunmores with his Beretta shotgun in the head and chest. The pair were found dead at their homes in villages six miles apart in Cambridgeshire.
The former quantity surveyor’s rampage came two days after a family court hearing involving Alderton’s grandson, who was the son of his daughter Samantha Stephen and Joshua, her ex-partner.
Judge Mark Bishop described the double murder as an ‘execution’. He told the defendant, who wore a silver crucifix necklace at court: ‘You took the decision to take the law into your own hands and end the lives of two innocent men.’
Alderton bowed his head as the judge sentenced him to life in prison with a minimum term of 25 years. As he was led to the cells a family member of the two dead men, who was in court, swore and shouted ‘rot in prison’, followed by brief applause.
Other members of the two men’s family wept as they filed out of the courtroom at Cambridge Crown Court following Monday’s sentencing.
Stephen Alderton (pictured), 67, has been sentenced at Cambridge Crown Court to life in prison with a minimum term of 25 years for the murders of father and son Gary and Joshua Dunmore.
The defendant pleaded guilty at an earlier hearing to the murders of Joshua Dunmore, 32, (pictured) and his 57-year-old father Gary Dunmore on March 29 this year
The pair were found dead at their homes in villages six miles apart in Cambridgeshire. Pictured is Gary Dunmore
Alderton, 67, shot Joshua Dunmore twice in the hallway of his home in Bluntisham, at 9.09pm. Thirty-one minutes later, he shot Gary three times in the hallway of his Sutton home.
Alderton fled in his motorhome but was arrested at about 1.30am the following day on the M5 near Worcester.
Before the killing, Cambridge Crown Court previously heard the killer grandfather had written in a series of text messages he would ‘override any court decision’ and that there was ‘always a plan B’ following the custody row.
After Alderton was arrested by armed officers, he told police that ‘sometimes you have to do what you have to do even if it’s wrong in the eyes of the law’, prosecutor Peter Gair said.
Judge Bishop added Alderton murderous rampage was sparked by his ‘distorted beliefs’ about family court proceedings involving his grandson ‘following what was an interim and not final hearing on March 27’.
Alderton was interviewed by police but did not answer any questions and was charged with two counts of murder and one count of possession of a firearm.
In June the defendant, of no fixed address, admitted the two counts of murder at Cambridge Crown Court. He denied the firearms offence, which was ordered to lie on file.
Barrister Mr Gair told the court Alderton had written in a telephone message last year: ‘I’ve a shortlist of people I intend to murder.
Former quantity surveyor Alderton went on a ruthless killing spree on March 29, repeatedly blasting the Dunmore’s with his Beretta shotgun
Police revealed a bag full of shotgun cartridges that Alderton had had in his possession
‘We say it’s clear that the events were triggered by an ongoing family court case between this defendant’s daughter Samantha Stephen, nee Alderton, and her former partner Joshua Dunmore,’ he told the court during an earlier hearing.
‘This concerned a request to move their seven-year-old child from the jurisdiction of the court by emigrating to the USA.’
He said that Mrs Stephen and Mr Dunmore’s relationship ended shortly after their son was born and in 2020 she married her current partner, Paul Stephen.
Mr Gair said that Mr Stephen, a US national, served with the US Air Force.
‘He was due to be redeployed back to the USA,’ said Mr Gair.
He said they ‘sought permission of the family court and Joshua opposed the application’.
‘There was a hearing on March 27 2023 and it would appear (the child) wouldn’t be removed from the jurisdiction,’ said Mr Gair.
The prosecutor said that when Alderton’s wife died in 2020, he had sold his home and was living at the time in a motorhome on a site in Willingham, Cambridgeshire.
He said Alderton was the holder of a shotgun licence and lawfully held a Beretta shotgun, which was used in both killings.
He said previous messages on Alderton’s phone reveal the defendant took an interest in the family court proceedings.
In October 2022 Alderton wrote: ‘I will override any court decision.’
Two spent shotgun casings are pictured on the floor in a photo today shared by police
In another message, Mr Gair said the defendant wrote: ‘There’s always a plan B’ and in further messages he talked of moving to Panama.
He said there were photographs of the homes of both Joshua and Gary Dunmore on Alderton’s phone.
Earlier on the day of the shootings, Alderton went to a storage lock-up in Huntingdon at 9.08am and then drove his white Peugeot car to their homes.
He met his daughter and her partner at McDonald’s in St Ives, Mr Gair said, making further visits to both men’s properties in the evening.
He was outside Gary Dunmore’s home in Sutton when he returned in his work van at 7.34pm and outside Joshua Dunmore’s home in Bluntisham at around 9pm when his girlfriend left, Mr Gair said.
Police said Joshua Dunmore was shot at 9.09pm and Gary Dunmore was shot 31 minutes later.
Mr Gair said it was likely Alderton knocked on Joshua Dunmore’s door and shot him ‘twice at close range’ when he opened it, in the left chest and the right side of his head.
He said this would have been ‘rapidly fatal’.
A neighbour saw the defendant ‘walking from Joshua’s house to his white car carrying a shotgun’, said Mr Gair.
‘The defendant placed it on his back seat before driving off.’
He said Gary Dunmore was also shot at close range and there were four shots.
‘The defendant had to reload as two shots can be fired from the shotgun,’ he said.
Mr Gair said ballistics experts say three shots struck Gary Dunmore and one missed and stuck in the staircase.
He said it is thought that the first two shots included the one that missed, with Mr Dunmore hit in the chest, and then in the top of his head and left hip.
More than 20 family members were packed into the courtroom, with some weeping as details were read and others listening remotely from a separate room within the court building.
Mr Gair said Alderton was ‘rapidly identified’ as a suspect due to the family court case and sightings of the white Peugeot.
His motorhome was picked up by police using ANPR (automatic number plate recognition) cameras.
He was stopped by armed police from the West Mercia force on the M5 near Worcester at about 1.30am on March 30, police said.
Mr Gair said Alderton was the sole occupant of the vehicle and ‘he volunteered that the shotgun was in the motorhome which it was’.
Earlier in the hearing, Judge Mark Bishop told family of the deceased: ‘I don’t want any hard staring of the defendant by the family members.’
He added: ‘We’re going to deal with this in a calm way.’
Forensics enter an address inside a police cordon at The Row, in Sutton, Cambridgeshire on March 30 2023 following a double shooting in the county
In a victim impact statement read to the court, Gary Dunmore’s mother Jane Phillips said: ‘Both were killed in the most vicious, cowardly way with no opportunity for self-defence.’
Mandy Seamark, mother of Joshua Dunmore, said in a statement read by Mr Gair that ‘words cannot describe the devastation’ of the defendant’s actions.
Adrian Langdale KC, mitigating for Alderton, said the defendant wrote in a letter to the court that ‘nothing can change the events of that night’.
He said Alderton, who worked for 25 years as a chartered quantity surveyor and had no previous convictions, had pleaded guilty to murder, describing this as a ‘rare’ thing.
He said the defendant was ‘realistic enough to know… he will never be released from prison’.
Alderton’s letter also said: ‘If I could turn back time I would.
‘I regret there are not enough words of remorse I can offer to the families affected by this crime.’
Mr Langdale said the defendant regarded the order from the family court as the ‘straw that broke the camel’s back’ and he had ‘tried hard to control his anger’.
In a letter, the defendant wrote: ‘I’m not the person that this conflict and the family courts have driven me to become.
‘I’ve never been a violent person, I do not have a criminal record.
‘I’ve been a respectable, law-abiding citizen all my life.
‘What happened to me on March 29 I do not know.’
Mr Langdale said Alderton’s grandson has been placed in care and ‘that’s a further burden upon’ the defendant.
Speaking on Monday, following Alderton’s sentencing, DCI Katie Dounias, from Cambridgeshire Police’s major crime unit, said: ‘On March 29, Stephen Alderton turned a family dispute playing itself out through the courts into a double tragedy by his rash and brutal actions.
‘Our thoughts are with the family and friends of Gary and Josh at this difficult time. There is no sentence sufficient to heal the trauma they have endured but I hope today’s sentencing will provide some solace.’