The whereabouts of a womanremained a mystery on Tuesday. Dunn, 19, was killed while riding his motorcycle in August. Authorities said Anne Sacoolas, who has been identified as the wife of a U.S. diplomat, was driving on the wrong side of the road when she hit Dunn. She then left the U.K. under diplomatic immunity.
"Some people must think it's very, very bizarre. We still don't wish her any harm because she's a mum. But very disappointed in humanity really, for her not to come forward and at least reach out somehow," mother Charlotte Charles told CBS News correspondent Imtiaz Tyab.
Charles and Dunn's father Tim Dunn are at the heart of a widening diplomatic dispute following their son's death in the head-on collision involving Sacoolas.
Sacoolas, a 42-year-old mother of three, is reportedly married to Jonathan Sacoolas, who was identified by British officials this week as a U.S. diplomat. There are court records showing she was convicted of a driving infraction in Virginia in 2006, for "failing to pay full time and attention" while behind the wheel.
British Prime Minister Boris Johnson urged the U.S. Embassy on Monday to re-think using immunity to protect Sacoolas.
"I do not think that it can be right to use the process of diplomatic immunity for this type of purpose," he said on a U.K. breakfast news show. "I hope that Anne Sacoolas will come back and will engage properly with the processes of law as they are carried out in this country. That's a point that we've raised or are raising today with the American Ambassador here in the U.K., and I hope it will be resolved very shortly. And to anticipate a question you might want to raise, if we can't resolve it then of course I will be raising it myself personally with the White House."
Diplomatic immunity is an international agreement that exempts diplomats and their families from prosecution in host countries. In rare cases it can be waived by a diplomat's home government. That is what Dunn's parents told CBS News they want the U.S. government to do — even if it means taking their case all the way to the White House.
"If we don't get any answers from staying here in the U.K., we still have plans to go to Washington," Charles said.
"Try and make our voice even more heard there," Tim Dunn said.
The bereaved parents have been promised a meeting with Britain's foreign secretary, who has been talking to his U.S. counterpart Secretary of State Mike Pompeo about the teen's death, but the family told CBS News the only person they want to talk to is Sacoolas.