Police say the woman drove a car onto the wrong side of the road and crashed into 19-year-old Harry Dunn, who was riding a motorcycle.

A US diplomat’s wife who was being investigated for her involvement in a deadly road accident that killed a 19-year-old in England has claimed diplomatic immunity and fled the UK after first telling authorities that she would not leave the country.

The accident happened outside RAF Croughton, a US Air Force base in the UK, in late August, according to Sky News.

Harry Dunn, 19, was riding a motorcycle on the correct side of the street when the 42-year-old woman, who had driven out of the air force base onto the wrong side of the road, hit him in a head-on collision, police said.

Dunn suffered multiple injuries and later died at a hospital, Sky News reported.

Police say the woman cooperated in their initial investigation, but then claimed diplomatic immunity and left the country before the investigation could be finished.

Diplomatic immunity is a cornerstone of international law and allows diplomats and their families to avoid civil and criminal prosecution while in a foreign country in their official capacity.

“Northamptonshire Police followed all of its usual procedures following the incident, including liaising closely with the suspect, who engaged with us at the time and had previously confirmed to us that she had no plans to leave the country in the near future,” the police said in a statement released Friday afternoon.

Officials said they’re “now exploring all opportunities through diplomatic channels to ensure that the investigation continues to progress.”

Sky News reported that the police applied for a diplomatic immunity waiver to continue the investigation, but the waiver was denied.

“I met Harry’s family yesterday. They are totally heartbroken,” Andrea Leadsom, a senior cabinet member and the parliamentary representative from South Northamptonshire, tweeted on Friday. “We have to get proper justice for Harry and closure for his family.”

Dunn’s family is asking President Donald Trump to send the 42-year-old woman back to the UK to continue the investigation.

“President Trump, please listen. We’re a family in ruin. We’re broken,” Charlotte Charles, Dunn’s mother, said during an interview with Sky News. “We can’t grieve. Please, please let her get back on a plane.”

“We have nothing. No justice. We have nothing to put our minds at rest that she’s even remorseful,” Charles said.

The US Embassy in London confirmed the involvement of a US diplomat’s wife in the incident, according to Sky News, and provided its “deepest sympathies” to Dunn’s family. The embassy said its officials are in “close contact” with British officials on the matter but would not confirm the identity of the woman for “security” reasons, according to the Telegraph newspaper.

The US State Department did not immediately responded for comment to BuzzFeed News.

Woody Johnson, the US Ambassador to the UK, also sent a letter to Dunn’s parents saying that he offered his condolences to the family.

Dunn’s family said in a statement released through the Justice4Harry Facebook page that they “will not rest” until the woman is brought back to the UK to “face the consequences of her actions.”

“It cannot be right that Harry’s life be ended in this manner without justice being done,” the family said. “It cannot be right that diplomats can simply be allowed to abscond to their own countries having committed a serious crime such as this one. No one is above the law. No one.”