The Foreign Secretary says Harry Dunn's alleged killer's role in intelligence had "no effect" on her diplomatic immunity claim.
In an interview on Sky News, Dominic Raab said "we don't comment on intelligence matters", when asked when he and the Prime Minister knew about Anne Sacoolas' role in the UK.
On 3 February this year, Mrs Sacoolas' barrister told a US court that the suspect and her husband Jonathan Sacoolas worked for the US State Department at the time of the crash and "fled" the UK due to "issues of security".
Mr Raab called the barrister's words "speculation".
Nineteen-year-old Harry Dunn died after his motorbike was involved in a crash outside US military base RAF Croughton in Northamptonshire, on 27 August 2019.
Lawyers acting on behalf of Mrs Sacoolas said she had driven on the "wrong side of the road for 20 seconds" before the collision.
After the incident, the 43-year-old US citizen had diplomatic immunity asserted on her behalf as the wife of a diplomat and she was able to return to her home country.
She was later charged with causing death by dangerous driving by UK authorities, but the US State Department declined a Home Office extradition request in January last year.
Last month, the American State Department reiterated its extradition refusal, calling the decision final.
The Foreign Office and Number 10 have both previously said the Foreign Secretary and the Prime Minister were unaware of the case until after Mrs Sacoolas had left the UK.
Asked if the US had failed to tell the UK Government about Mrs Sacoolas' role in intelligence, Dominic Raab told Sky News: "We don't comment on intelligence matters but what I can say categorically is that her status was as the partner or the spouse of an officer of the Embassy.
"The other speculation had no impact and wouldn't have had any effect on the status that she had in the UK."
The High Court previously ruled that Mrs Sacoolas had diplomatic immunity at the time of the crash due to a clause that meant dependants of US Embassy employees were entitled to immunity.
That "anomaly" was closed by the Foreign Office in July last year.
Questioned on when he found out about Mrs Sacoolas' intelligence role, Mr Raab continued: "We've been clear with the family as well about this. Her status was very clear and it was based on her being the wife of an officer of the Embassy up at Croughton.
"That was the basis on which she had immunity. We, of course, wanted it waived and wanted her to be returned after she left and that remains our position."
The Dunn family's spokesman Radd Seiger said: "It is now 10 days since Anne Sacoolas' own lawyer revealed that she was working for the intelligence agencies at the time of the crash.
"We have heard nothing whatsoever from officials in London by way of explanation.
"The silence is deafening, and the parents are suffering from extreme stress over the issue.
"It is not true that Mr Raab does not comment on intelligence matters.
"We asked him this very question when we met with him on January 28 last year when his response was merely that 'she used to work for the State Department'.
"That statement is at odds with what Mrs Sacoolas's lawyer said.
"Given the importance of the matter, one might have thought that someone at the Foreign Office would have picked up the phone to us to offer a meeting.
"None of us want to know what Mrs Sacoolas was doing at the time. We presume she was working to keep us safe.
"But it is no good Mr Raab being economical with the truth when face-to-face with the parents in January 2020 and now refusing to answer the very simple question of who knew what and when on national television."
Cover image: Harry Dunn (Picture: Justice4Harry).