The family of Harry Dunn, the 19-year-old British motorcyclist killed in a crash when a car was driven on the wrong side of the road in Northamptonshire last August, filed a federal lawsuit in the United States against the American driver on Wednesday. The lawsuit, filed in federal court in Virginia, claims wrongful death and seeks financial damages. The suing of Anne Sacoolas, the driver of the car and the wife of an American diplomat, who was living in the UK at the time, is a notable escalation in a campaign for justice by Dunn’s family that has strained US-UK relations. The crash happened on a country road outside RAF Croughton on 27 August last year. Sacoolas claimed diplomatic immunity and quickly left the UK, returning to her home in northern Virginia, and the US government backed up her claim of immunity in the case. Sacoolas is the wife of diplomat Jonathan Sacoolas, who is also named as a defendant in the lawsuit. Britain’s foreign office had formally asked the US embassy to waive immunity early last September but was rebuffed, with the embassy telling the British government that Anne Sacoolas was leaving the country. The lawsuit was filed by Dunn’s parents, Charlotte Charles and Tim Dunn, as well as his twin brother, Niall Dunn, against Anne and Jonathan Sacoolas. It alleges that Anne Sacoolas left the scene rather than helping the gravely injured teen. “Defendant Anne Sacoolas did not call an ambulance for Harry,” the lawsuit alleges. “Instead, she left Harry to suffer as he lay face down on the side of the road, afraid of dying, fully conscious with multiple broken bones, including open fractures on both legs and both arms, and internal injuries.” It adds: “Tragically, Harry died as a result of the catastrophic injuries he suffered in the accident.” Dunn’s parents later traveled to the US in an attempt to persuade US authorities to extradite Anne Sacoolas. Last December, British police charged her with causing death by dangerous driving. A British request for extradition was rejected. The lawsuit emphasized that Dunn was riding his motorcycle safely and taking proper protective cautions. “Harry was properly licensed, well rested, and very familiar with his motorcycle, with riding motorcycles in general, and with the B4031 roadway,” the suit explained. “He was wearing a full-face helmet for protection and was riding his motorcycle properly and within the law. He had his lights on, was not under the influence of any alcohol or drugs, was traveling within the speed limit, and was not talking or texting on his phone.” The court filing lists Dunn’s injuries in detail. And it adds that “he was catapulted off his motorcycle and into the front of her [Sacoolas’s] SUV, leaving blood and clothing embedded in the front windshield, and landed to the side of the SUV.” The 19-year-old suffered only a minor head injury and did not lose consciousness. “He was conscious during and after the impact. He lay awake, alone, and in pain, knowing that he was badly hurt and dying, facedown by the side of the road,” the lawsuit states. Charlotte Charles said in a statement on Wednesday that it was “unfathomable” that Harry had been dead for almost a year and the family still did not know the truth of what happened and that Anne Sacoolas had not faced legal consequences. Agnieszka Fryszman, a partner at Cohen Milstein Sellers & Toll in Washington DC who is representing the family, said that she felt the push for justice was even more important in this case after seeing “Harry’s lovely parents” and brother suffer such heartbreak. “Given Ms Sacoolas’ refusal to return to the UK, we look forward to bringing this case to a jury of Anne Sacoolas’ peers here in the United States,” she said. Last October, Dunn’s parents visited the White House following an invitation by Donald Trump, only to be confronted with the president telling them without warning that Anne Sacoolas was waiting for them in an adjoining room and wished to meet them. Dunn’s parents declined the offer. The family has also been critical of the British government’s failure to take more action and bring about resolution in the case. On Wednesday, Charles said: “Fighting for justice for Harry has been and will remain our number one priority because of a promise we made to him the night we lost him.”