Stephen Alderton: widower sentenced to life after shooting dead daughter's ex-partner and his father

A widower who shot dead his daughter's ex-partner and her ex-partner's father over a family court case involving his grandson has been sentenced to life in prison with a minimum term of 25 years.

Stephen Alderton, 67, shot and killed Joshua Dunmore, 32, and his 57-year-old father Gary Dunmore on 29 March 2023. Both were found dead separately at their homes six miles apart, with Joshua found at his home in Bluntisham and Gary found at his property in Sutton. The shootings took place two days after a family court hearing.

Cambridge Crown Court heard that Alderton has written in previous text messages that he would "override any court decision” regarding the decision over custody of his grandson, adding that there was "always a plan B". After Alderton was arrested by police by armed officers on the motorway hours after the killings, he told police: "Sometimes you have to do what you have to do even if it’s wrong in the eyes of the law."

Prosecutor Peter Gair told the court: “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 seven-year-old child from the jurisdiction of the court by emigrating to the USA.”

The court heard that Ms Stephen and Mr Dunmore broke off their relationship shortly before the birth of the child. In 2020, she married her current partner, Paul Stephen. Mr Stephen, a US national who served in the US Air Force, was due to be redeployed back to the US, with Mr Dunmore opposing the application to the family court to remove the child from the UK. Mr Gair added: “There was a hearing on March 27 2023 and it would appear (the child) wouldn’t be removed from the jurisdiction."

Adrian Langdale KC, mitigating for Alderton, said that the defendant had lost his wife in December 2019. Mr Langdale said Alderton 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.”

Judge Mark Bishop described the fatal shootings as an "execution". He told Alderton in the court: “You took the decision to take the law into your own hands and end the lives of two innocent men.” Judge Bishop added that Alderton had taken the extreme step over his "distorted beliefs" about the family court hearing involving his grandson “following what was an interim and not final hearing on March 27”.