reported that the alleged driver is the wife of a US diplomat who was later advised to leave the UK by the American Embassy.
She left claiming diplomatic immunity - which allows unhindered travel for Government envoys and their families.
Harry's family said they were comforted that the teen had been driving safely the night of his death Credit: Facebook The teen's parents said they were devastated by their son's death Credit: Sky News An attempt by Northamptonshire Police to stop her leaving was declined - and the US Embassy has confirmed she's no longer in the UK.
Harry suffered multiple injuries in the crash and later died in hospital.
The case has prompted a response from the British Foreign & Commonwealth Office.
Last night, Foreign Secretary Dominic Raab said: "I wish to offer my condolences to the family affected by this tragic incident.
"I have called the US Ambassador to express the UK's disappointment with their decision and to urge the Embassy to re-consider it."
The unnamed suspect was reportedly advised by embassy officials to leave the UK - causing further pain to tragic Harry's family.
Paying tribute to Harry, mum Charlotte added: "Everyone loved him, we're utterly broken inside and out.
"Everything hurts day and night, it's an effort to do anything, I ache from it, every limb, every internal organ hurts.
"We don't know how we can start to grieve for him.
"We have nothing. No justice.
"We have nothing to put our minds at rest that she's even remorseful."
FAMILY'S DISGUST Harry's father, Tim Dunn, said: "We're disgusted, appalled, how she could be having this cloak wrapped around her.
"I'm angry that someone could do this and then get on a plane and go. I can't believe she's living with herself."
The family received a letter expressing "profound sadness" from the US ambassador to the UK Woody Johnson.
But efforts to contact the American suspect have been met with silence.
I have called the US Ambassador to express the UK's disappointment with their decision and to urge the Embassy to re-consider it
Dominic Raab Foreign Secretary Superintendent Sarah Johnson, Head of Operations for Northamptonshire Police, confirmed the 42-year-old American suspect had left the country.
She said: "Northamptonshire Police followed all of its usual procedures following the incident, including liaising closely with the suspect, who engaged fully with us at the time and had previously confirmed to us that she had no plans to leave the country in the near future.
"Due process was also followed in seeking the necessary documentation to allow for the arrest and formal interview of the suspect, and the Force is now exploring all opportunities through diplomatic channels to ensure that the investigation continues to progress.
"We are also working closely with the Foreign & Commonwealth Office in an effort to come to a resolution regarding this matter. “Harry Dunn’s family deserve justice and in order to achieve this, a full and thorough investigation, with the assistance of all parties involved, needs to take place.
"Northamptonshire Police is committed to ensuring justice for Harry and specially trained officers continue to support the Dunn family in their loss, including keeping them fully informed of all developments in the investigation."
In a statement, the US Embassy in London said: "We express our deepest sympathies and offer condolences to the family of the deceased in the tragic August 27 traffic accident involving a vehicle driven by the spouse of a US diplomat assigned to the United Kingdom.
"Embassy officials are in close contact with the appropriate British officials on this matter.
"Due to security and privacy considerations, we cannot confirm the identity of the individuals involved, but we can confirm the family has left the UK".
Harry, seen in a social media photo, was killed while riding his motorbike in August Credit: Facebook RAF Croughton in Northamptonshire, where the horror crash took place (file photo) Credit: PA:Press Association
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