British police investigating the death of teenage biker Harry Dunn will travel to the US to interview the diplomat's wife who is accused of killing the 19-year-old.
Harry Dunn, 19, died after a car driven down the wrong side of the road by Anne Sacoolas is alleged to have collided with his motorbike near RAF Croughton, an air force base in Northamptonshire used by the US military.
Sacoolas fled the UK shortly after Harry's death and American authorities have refused to send her back to the UK.
Now, Harry's family have been told that UK police officers will travel to interview Sacoolas.
A source told Sky News: 'The chief constable will speak to the press tomorrow (Tuesday) and confirm that officers will visit the US and conduct an interview with the suspect.'
It is not known whether a meeting between Sacoolas and police officers has been arranged.
The latest development comes as the family of Harry Dunn slammed foreign secretary Dominic Raab.
They said they are 'as angry as they have been' after the foreign secretary admitted in the House of Commons yesterday that the US told Britain Sacoolas was planning to leave the country, but UK police were unable to legally stop her.
In a furious response to Raab's statement, the spokesman for Harry Dunn's family Radd Seiger said: 'The family just has absolutely no confidence in Dominic Raab.
'He said we didn't go to him or his department for help while we were in the United States - that's because he is the last person we would go to for help after the meeting we had with him.
'The family are angry tonight. They are probably angrier now than they have been at any stage in this entire process.
'Dominic Raab said the ball is in Northamptonshire Police's court for keeping us up-to-date with the investigation. The chief constable has told us he can't answer the questions we had for him. Somebody is lying and the family are sick of it.'
The foreign secretary revealed earlier that Britain is reviewing the rules that allowed Sacoolas to flee after the fatal car crash.
Raab told the House of Commons: 'I have already commissioned a review of the immunity arrangements for U.S. personnel and their families at Croughton.
'As this case has demonstrated, I do not believe the current arrangements are right and the review will look at how we can make sure that the arrangements at Croughton cannot be used in this way again.'
He added that the government will 'continue to fight for justice' for the Dunn family.
Raab also claimed there are 'no barriers to justice being done' in the case.
The UK Government believes diplomatic immunity 'clearly ended' for Sacoolas when she left the country, the foreign secretary said.
He added it would be for the Crown Prosecution Service (CPS) and police to decide what steps to take, telling MPs he is 'not aware of any obstacle' under the UK/US Extradition Treaty.
Raab's remarks followed questions from Labour and others, including if he had been advised whether the CPS could commence extradition proceedings to return Mrs Sacoolas to the UK.
Shadow foreign secretary Emily Thornberry raised several questions, including why it took so long for the family to be informed that Sacoolas had returned to the US.
Thornberry added: 'Given (Mr Raab) has made it clear that the supposed diplomatic immunity status granted to Mrs Sacoolas has ceased to apply since her return to the United States, I'm not asking him to intrude on independent decisions of prosecuting authorities, but has the Foreign Secretary been advised as to whether there are any barriers to the CPS commencing extradition proceedings to return Mrs Sacoolas to the UK?'
Addressing the delay in informing Mr Dunn's family about Mrs Sacoolas's departure, Raab replied: 'It was one or two days.
'The reason we asked for a little bit of time - and this was a request not made by me, I wasn't aware of it, but by my officials - was to make sure we'd be very clear on what the next course of action would be, and indeed precisely so they could inform ministers before the family were aware because we were aware there'd be immediately questions that would come back about what we'd do next.'
On barriers to justice, Mr Raab said: 'Ultimately that must be for the CPS and police to decide and we're in close contact with them.
'I am aware there are no barriers to justice being done in this case.
'And at every stage during this process I have been, and my officials have been, keen to make sure we can remove any obstacles to justice being done.'
SNP MP Stephen Gethins (North East Fife) said that if the CPS seeks extradition, the US authorities must co-operate.
Gethins added: 'Special relationship or none, these things have to go both ways, and that means that the US authorities must co-operate fully. And by saying co-operate fully, it means if the Crown Prosecution Service seek an extradition, I know he can't comment on this, then extradition must be given.'
Raab replied: 'He asked about pressure on the United States, we have made clear our disappointment with the refusal to waive and we have requested a reversal of that decision at every level of the administration, from the ambassador here through to the representations the Prime Minister made to the US president.
'He asked about requests for extradition, and they would of course be made by the CPS. Under the UK/US Extradition Treaty, I'm not aware of any obstacle, but I would once again be very mindful of the responsibility I've got not to say anything prejudicial.'
It comes after Harry Dunn's parents admitted their hopes of meeting the woman who is said to have killed their son while driving on the wrong side of the road have 'become quite slim', following a meeting with President Donald Trump in the White House.
Tim Dunn and Charlotte Charles revealed their Oval Office meeting with Trump failed when National Security Adviser Robert O'Brien made clear Anne Sacoolas would under no circumstances be returning to the UK.
The distraught parents said: 'O'Brien was there next to Trump and he said 'she is never coming back to the UK,'' before describing him as 'quite aggressive.'
The pair then emotionally explained how they refused to meet Mrs Sacoolas, who was in another room waiting for a reconciliation, because they promised their late son that they would get justice for him on UK soil.
Ms Charles said: 'Our immediate reaction was no straight away. We made a promise to Harry and we said we would get justice on UK soil because the evidence was already there.
'If we meet her we need therapists around us, we don't want to be thrown together.'
'We hoped that she would do the right thing as a human and face the justice system. We would still work with her but to be honest our hopes of meeting have become quite slim.'
Speaking on This Morning with Eamon Holmes and Langsford, the bereaved parents accepted that there is a chance they won't get the justice they want.
Ms Charles said: 'They were aware we were going to work with police to get her sentence suspended so she wouldn't be taken from her children.
'We have considered that we may not win but if justice means not getting her back but getting the truth then that's a win.
'We want to know who made the decision for her to go? When did she go? Who allowed her to leave?
Tim: 'They lied to us. They said she had immunity and then didn't have immunity.'
The pair then cast doubt on the efforts of the Foreign Secretary, telling viewers they were 'sceptical' after Dominic Raab admitted to them he delayed informing them that Mrs Sacoolas had left the country.
Ms Charles then made an emotional plea to Mrs Sacoolas, who ploughed into 19-year-old Harry Dunn while driving on the wrong side of the road near RAF Croughton in Northamptonshire.
She said: 'Come back to the UK. We're not horrible people.
'We know she must be suffering - her two children were in the car - they must be suffering too. We want her to come back.'
Previously, Harry's family called for prosecutors to 'get on with it' after learning vital evidence has been passed on to them.
Ms Charles and Mr Dunn were told that police have handed their file to the Crown Prosecution Service (CPS).
The evidence includes CCTV footage of US citizen Mrs Sacoolas, 42, driving on the wrong side of the road outside RAF Croughton – a spy hub in Northamptonshire – almost eight weeks ago before crashing head-on into the 19-year-old motorcyclist.
She used her husband's status as a US intelligence officer to claim diplomatic immunity before leaving Britain.
But her immunity from prosecution has expired because he is no longer in his post, according to the Foreign Office.
The CPS will decide whether the evidence is strong enough for charges to be brought. Then an extradition request could be made to the US for her arrest.
Last night, Radd Seiger, a spokesman for Harry's parents, urged the CPS to make a quick decision to avoid keeping the family 'stuck in limbo'.
He said: 'Come on, let's get on with it. For us that would be a big step if an extradition request was submitted to the US.
'That would be one giant step towards achieving closure. It's not a game – this family are grieving.'
Labour has called for an urgent parliamentary inquiry into the Government's handling of the case after the Foreign Office admitted hiding information from the teenager's family.
Police were told Mrs Sacoolas had left Britain on September 16 after being granted diplomatic immunity.
Harry's parents claim they were not informed until ten days later.
Shadow Foreign Secretary Emily Thornberry said: 'It now looks increasingly clear that the Foreign Secretary and his officials have something to hide in terms of how they responded to this dreadful tragedy.
'The rights, justice and answers that are due to Harry Dunn's grieving family can no longer be denied.'
Meanwhile donations to Harry's campaign more than doubled during his family's visit to the US.
Harry's parents, Charlotte Charles and Tim Dunn spent all of last week in the US, participating in a number of high profile media interviews and also had a controversial meeting with Donald Trump.
Prior to leaving, Harry's GoFundMe page stood at just over £30,000 with a target to reach £75,000.
Since the widespread coverage of their US trip, it now stands at over £66,000 and the target has been increased to £100,000.
The money has been raised from 2,000 donors from 24 countries including New Zealand, Canada, France, Germany, Netherlands and Portugal.
Mr Seiger described the US trip as 'highly successful.'
Mr Seiger added: 'Since that appeal, the family can't quite believe the wonderful further support they are receiving from the public and are frankly overwhelmed as they have watched the donations flood in.
'They are incredibly grateful from the bottom of their hearts for all this support.'