The Chief Constable of Northamptonshire Police says they will treat Anne Sacoolas like any other wanted person.
Mrs Sacoolas is wanted for questioning about the death of Harry Dunn, the 19-year-old knocked off his bike on a road near RAF Croughton.
He had collided with a car driving on the wrong side of the road.
Shortly after the crash Mrs Sacoolas, the wife of a US diplomat working in the UK, was granted diplomatic immunity and flew to America.
WATCH: Chief Constable Nick Adderley, Northamptonshire Police
Speaking on Friday morning, Chief Constable Nick Adderley said: "We will go through the process that we would with anybody who’s not subject to diplomatic immunity.
"We would look to circulate that person as 'wanted' on the police national computer, we would look to consider the options we have in starting extradition proceedings.
"What we’ve got to do is be ready so that if anything changes we’re in a position to go.
"We will not row back or slow down from doing this exactly as we would if this was any other case where somebody was not available or making themselves availed for part of that investigation enquiry."
Boris Johnson has spoken to President Trump, encouraging him to allow Mrs Sacoolas to return to the UK.
However, there has been nothing from the US Government to suggest that they will act as requested.
Mr Adderley also said they will be passing on all the information they have to the Crown Prosecution Service (CPS) in the next few days.
He added: "We are moving at pace in terms of putting that file of evidence together.
"The fact that the driver of that vehicle is not in the country will not slow us down in terms of putting that evidence to the CPS.
"Once the CPS have come back with a decision on what to charge - if anything - and hopefully that will be early next week, we will then start the process of deciding what we do next."