Harry Dunn, 19, was killed when his motorbike crashed into a vehicle on 27 August and the suspect in the case, 42-year-old Anne Sacoolas, the wife of a USA intelligence officer, was granted diplomatic immunity following the crash.
US President Donald Trump says that a British teenager killed in a crash allegedly caused by the wife of an American diplomat was the victim of a "terrible accident", adding that driving on the wrong side of the road "happens".
"The woman was driving on the wrong side of the road and that can happen, you know", Mr Trump said.
In a press conference on Wednesday, Mr Trump said wrong-way driving "happens" after being asked by Prime Minister Boris Johnson to reconsider granting immunity to Mrs Sacoolas.
The 19-year-old motorcyclist, Harry Dunn, was killed.
U.K. Prime Minister Boris Johnson spoke to President Donald Trump on the evening of October 10 to urge President Trump to reconsider the US position so that the diplomat's wife can return to the U.K., cooperate with police and allow Harry's family to receive justice, a Downing Street spokesperson said.
Since Harry Dunn's death, his parents, Tim Dunn and Charlotte Charles, have tirelessly campaigned for justice, calling on British and American officials to help hold Sacoolas accountable.
"It's just beyond any realm of any human thinking".
However, where crimes are committed, the Foreign Office can ask a foreign government to waive immunity.
Number 10 said the prime minister had urged Mr Trump to reconsider the decision to allow Mrs Sacoolas immunity in order that "the individual involved can return to the United Kingdom, co-operate with police and allow Harry's family to receive justice".
Mr Dunn has welcomed the idea of speaking with Mrs Sacoolas.
"He must know where she, the kids, the husband are - whether they are being hidden or they've just run away - one way or another he must know exactly where they are".
"We will keep the pressure on - we still don't understand, none of us as a family, everyone around the world that keeps contacting us".
Trump on Wednesday called what happened "a awful accident" and said his administration would seek to speak with the driver "and see what we can come up with".
Radd Seiger, a lawyer acting on behalf of Harry's household, said he was once "happy" Mr Trump had develop into fervent, and said he hoped he was once "correct for his observe" on his comments that his administration would talk to Mrs Sacoolas.
Following the fatal crash, Ms Sacoolas claimed diplomatic immunity under worldwide law, allowing her to avoid prosecution and return to the USA - despite telling officials she had no plans to do so.
"But not every driver has travelled the distance that Anne Sacoolas did and taken the life of a 19-year-old who was completely and utterly innocent".
He said: 'The woman was once driving on the imperfect facet of the avenue, and that might maybe perhaps well happen.