A chief constable has written to the US Embassy in London demanding the return of an American diplomat’s wife who is a suspect in a fatal crash inquiry.
Harry Dunn, 19, died when his motorbike hit a car near RAF Croughton in Northamptonshire in August.
The diplomat’s wife left the UK despite telling police she did not plan to.
Nick Adderley, of Northamptonshire Police, has written “in the strongest terms” to the US Embassy urging them to waive her diplomatic immunity.
On Saturday the US State Department said diplomatic immunity was “rarely waived” but Foreign Secretary Dominic Raab urged the US Embassy to reconsider.
Under the 1961 Vienna Convention, diplomats and their family members are immune from prosecution in their host country, so long as they are not nationals of that country. However, their immunity can be waived by the state that has sent them.
Mr Adderley was asked on Twitter whether the woman was lawfully entitled to claim diplomatic immunity.
He replied: “The short answer is yes,” adding that both he and Northamptonshire Police and Crime Commissioner Stephen Mold had written to the US Embassy, urging that the waiver be applied “in order to allow the justice process to take place”.
Mr Dunn’s mother, Charlotte Charles, has told the BBC the family has been left “utterly devastated” by the death of the teenager, from Charlton, Banbury, on 27 August.
Mrs Charles told the BBC: “We’re really hoping to try to get her back; from me, as a mum, to her, as a mum, you just hope that he [Mr Raab] can try to get through to her.
“We don’t wish her any ill harm, but we don’t understand how she can just get on a plane and leave our family just utterly devastated.
“If we don’t get any luck over here, then we will go over there.”
The US State Department said on Saturday that the incident involved “a vehicle driven by the spouse of a US diplomat assigned to the United Kingdom”.
Police said that the suspect “engaged fully” following the crash near RAF Croughton, a US Air Force communications station, and said “she had no plans to leave the country in the near future”.
The US Embassy in London said that “security and privacy considerations” precluded it from naming the suspect.
The US State Department has said it is in “close consultation” with British officials and has offered its “deepest sympathies” to the family of Mr Dunn.
“Any questions regarding a waiver of immunity with regard to our diplomats and their family members overseas in a case like this receive intense attention at senior levels and are considered carefully given the global impact such decisions carry; immunity is rarely waived, ” it added.