Anne Sacoolas and her husband Jonathan have been told they will be “deposed” by July 23 this year – meaning they will give their account of events under oath in front of Mr Dunn’s mother Charlotte Charles and father Tim Dunn.
The deposition will form part of the “discovery” process in the Dunn family’s civil claim, in which correspondence and documentation relevant to the case will be handed over ahead of a trial at the end of the year.
Mr Dunn, 19, was killed when a car crashed into his motorbike outside US military base RAF Croughton in Northamptonshire in August 2019.
Sacoolas, 43, had diplomatic immunity asserted on her behalf by the US Government following the incident and was able to return to her home country.
She was charged with causing death by dangerous driving but the US State Department have described their refusal to extradite her as “final” on a number of occasions.
The Dunn family’s civil claim has unearthed a great deal of previously unheard material, such as the State Department roles held by both Mr and Mrs Sacoolas.
The Alexandria District Court in the US State of Virginia heard the couple’s work in intelligence was a “factor” in their departure from the UK – with the Sacoolases leaving for “security reasons”.
Lawyers acting on behalf of Mr and Mrs Sacoolas have also submitted their “answers” to the civil proceedings – asserting their objections to certain parts of the claim.
Judge Thomas Ellis gave the civil claim the go-ahead earlier this month.
Mr and Mrs Sacoolas’s legal team have asserted that various parts of the civil claim are “not supported by the law of England and Wales” and reject the prospect of a jury trial as that is not “pursuant to the law of England and Wales”.
The scheduling order, issued on Tuesday, has informed both parties that the next hearing in the case will be heard on April 21.
Reacting to the scheduling order issued on Tuesday, family spokesman Radd Seiger told the PA news agency: “The court in Virginia has now set out the timetable for the parties to follow in the civil claim to trial.
“This is another giant step for Harry’s family towards achieving justice for Harry.
“We set off to Washington shortly after Harry died in search of answers and justice and by no later than July 23 both Mr and Mrs Sacoolas will be required give testimony under oath in front of Charlotte and Tim.
“This will hopefully allow them to process what happened to Harry as they seek to rebuild their shattered lives.”