LONDON — The devastated parents of a British teenager who police say was killed by the wife of a U.S. diplomat in a wrong-way collision in August said Tuesday in a televised interview that they are willing to travel to the United States to get justice for their son.

After the crash, 42-year-old suspect Anne Sacoolas claimed diplomatic immunity under international law, allowing her to avoid prosecution and fly home to the United States — despite telling British police she had no plans to do so.

In the weeks since Harry Dunn, 19, died after a Volvo SUV struck his motorcycle, his parents, Tim Dunn and Charlotte Charles, have said they will not stop trying to obtain justice. They have appealed to British Prime Minister Boris Johnson and President Trump to assist them in their quest.

Harry’s parents say they hope Trump will consider waiving diplomatic immunity so that Sacoolas could be held accountable in the British legal system. The U.S. Embassy noted in a statement that “immunity is rarely waived.”

“With the amount of diplomats we have in the U.K., we can’t have someone go out and do something like that again and leave another family to suffer,” Charles said in an interview Tuesday with the “BBC Breakfast” program.

The parents also said during the interview that they had heard “absolutely nothing” from the Sacoolas family since the fatal collision near the Royal Air Force Croughton station, which is operated by the U.S. Air Force.

British news media have reported that Sacoolas and her diplomat husband had been in Britain for only about three weeks when the crash occurred. Local police said surveillance video showed that a vehicle left the Croughton base “on the wrong side of the road” on the night of the crash. Those factors raised the prospect that the collision may have stemmed from the inexperience of a motorist unaccustomed to driving on the left, as is the rule in Britain.

“As a mother myself, it’s really distressing not to have any word” from Sacoolas, Charles said. “It doesn’t sit well with me.”

She added: “The whole family desperately want to grieve, but we can’t, so every day is a battle.” She said her son had a twin brother, who has now “lost his twin-ship and his partner in crime.”

The teenager’s death has sparked widespread outrage in Britain and, in recent days, has garnered international interest. Harry’s parents say they have received condolences and supportive messages from around the world.

“The messages of support we’ve had from the U.S. have been immense. They’re all appalled and devastated for us and disgusted that this woman has been allowed to leave the U.K.,” Charles said.

“We are determined to see it through. We won’t stop. We will go to Washington if we have to,” she added.

“Maybe President Trump will look at this and hopefully look in our favor,” Tim Dunn said.

Johnson expressed hope Monday that Sacoolas would return to Britain and “engage properly with the processes of law.” The prime minister added that he was willing to raise the case “personally with the White House,” if necessary.

In a tweet Tuesday, Woody Johnson, the U.S. ambassador to Britain, said British Foreign Secretary Dominic Raab and his U.S. counterpart, Secretary of State Mike Pompeo, had “discussed the tragic death of a British citizen in a traffic accident on August 27 near Croughton” on Monday. “We once again express our condolences to the friends and family of Harry Dunn,” Johnson said.

While Sacoolas was named in British media reports and by the prime minister as the person suspected of driving the vehicle that knocked the 19-year-old off his motorcycle, the State Department on Monday declined to confirm her involvement in the case.

Family members of diplomats living in other countries are covered by immunity under the 1961 Vienna Convention on Diplomatic Relations. In most circumstances, this allows them to avoid arrest for virtually any crime. A country can also waive its diplomats’ immunity if it so chooses.

On Tuesday, Dunn’s parents described him as a “big-hearted” person and “passionate” biker who “lived to ride.”