In this file photo, Charlotte Charles, left, the mother of teenage motorcyclist Harry Dunn who was killed in a collision with a car by US citizen Anne Sacoolas, stands beside her husband Bruce Charles, right, as they speak to members of the media before a meeting with Britain's Foreign Secretary and First Secretary of State, Dominic Raab at the Foreign and Commonwealth Office in central London on Jan 27, 2020. (PHOTO / AFP)

UK authorities were correct to allow an American diplomat’s wife to leave the country after a 2019 car accident that killed a young man outside an air force base, a British court ruled Tuesday.

Anne Sacoolas had diplomatic immunity through her husband’s job when she killed 19-year-old Harry Dunn while she was driving on the wrong side of the road outside RAF Croughton in Northamptonshire, judges Julian Flaux and Pushpinder Saini said.

Anne Sacoolas had diplomatic immunity through her husband’s job when she killed 19-year-old Harry Dunn while she was driving on the wrong side of the road outside RAF Croughton in Northamptonshire

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Dunn’s family has urged Prime Minister Boris Johnson to seek the return of Sacoolas to the UK to face charges. They sued the UK government, arguing that British officials unconstitutionally intervened in the investigation and allowed Sacoolas to flee to the US.

“In our judgment, Mrs Sacoolas had immunity at the time of Harry’s death,” the judges wrote in their ruling.

UK Foreign Secretary Dominic Raab said the government wants Sacoolas to return to the country to face justice, and said it would support the Dunn family’s legal actions in the US.

“My thoughts today are with Harry’s family,” Raab said in an emailed statement. “While this judgment makes clear the Foreign Office acted properly and lawfully throughout, I appreciate that won’t provide any solace to the family in their search for justice.”

In October 2019, the Dunns met President Donald Trump at the White House, where he tried to arrange a meeting with Sacoolas. The family left without talking to her, saying they wanted to interact on their terms.

Dunn’s family vowed to continue to fight.

READ MORE: UK charges wife of US diplomat over teen's death in crash

The US Embassy in London, and Sacoolas’ attorney in the US didn’t return emails seeking comment.

Geoffrey Robinson, an attorney for the Dunns, said at a hearing earlier this month that the Foreign Office improperly pressured the police not to charge Sacoolas, and then allowed her to leave.

“Diplomatically, it was easy to put the family on a plane because she hadn’t been interviewed or charged,” Robinson said. “It would be highly unlikely for an allied country to put someone on a plane once they’ve been charged.”

James Eadie, the government’s attorney, argued that international law dictated the treatment of Sacoolas.

“She enjoyed the privileges and immunities that rose automatically” from her husband’s post, Eadie said.

The immunity didn’t mean the investigation into the August 2019 accident stopped, Eadie said. The local police didn’t interview Sacoolas, but they took statements from emergency workers who talked to Dunn before he died and looked at phone and security video data.