This is the moment armed police arrest a double killer who gunned down his daughter’s ex and his father.
Widower, Stephen Alderton shot dead Joshua Dunmore, 32, and his dad Gary Dunmore, 57, over a family court case involving his grandson.
Prosecutor Peter Gair said former chartered quantity surveyor Alderton blasted the two men with his Beretta shotgun on March 29, two days after a family court hearing.
Alderton, 67, of no fixed address, had written in text messages he would “override any court decision” and there was “always a plan B”, Cambridge Crown Court heard.
The defendant, who pleaded guilty to the murders at an earlier hearing, was sentenced on Monday (October 23) to life in prison with a minimum term of 25 years.
Footage of the arrest shows armed police bring a motorhome to a halt on the motorway before an officer can be heard shouting at Alderton: “Armed police, you, get out of the car. Get out of the car now.”
Alderton, dressed mainly in black and wearing a baseball cap, can be seen slowly pushing the driver’s side door open, emerging with his hands up in the video captured soon after the murders.
Judge Mark Bishop described the murders as an “execution”, telling the defendant, who wore a silver crucifix necklace in court: “You took the decision to take the law into your own hands and end the lives of two innocent men.”
He said Alderton did this over his “distorted beliefs” about family court proceedings involving his grandson “following what was an interim and not final hearing on March 27”.
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”, which was followed by brief applause.
Joshua and Gary Dunmore were found dead at their homes in villages six miles apart in Cambridgeshire, with Joshua’s home in Bluntisham and his father’s in Sutton.
Mr Gair told the court after Alderton’s arrest hours after the murders, he told police “sometimes you have to do what you have to do even if it’s wrong in the eyes of the law”.
He added: “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.
“This concerned a request to move their child from the jurisdiction of the court by emigrating to the USA.”
He said 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 Mr Stephen, a US national, served with the US Air Force, adding he was due to be redeployed back to the USA.
He said they sought permission of the family court and Joshua had opposed the application.
Adrian Langdale KC, mitigating for Alderton, said the defendant’s wife died in December 2019.
Mr Gair said Alderton sold his home and was living at the time of the offences in a motorhome on a site in Willingham, Cambridgeshire.
He added Alderton was “rapidly identified” as a suspect after the shootings 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, according to the police.
Mr Langdale said the defendant wrote in a letter: “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.”
