The family of crash victim Harry Dunn are considering a private criminal prosecution against an American diplomat's wife suspected of being responsible
Anne Sacoolas, the motorist allegedly responsible for the crash, claimed diplomatic immunity and was allowed to return to the US
Family spokesman Radd Seiger said Mr Dunn's parents were going through "untold mental anguish" caused by what they call a "delay" in a charging decision in the 19-year-old's case..
In a statement on Monday, Mr Seiger said it "boggles the mind that no charge has yet been laid" and added that discussions about a private prosecution were under way.
He said: "Sadly, the family are losing faith and confidence in the criminal justice agencies to do the right thing and authorise that charge and have therefore reluctantly concluded that they have no choice other than to now actively consider with their lawyers in London bringing a private criminal prosecution against Anne Sacoolas.
"Those discussions are now well advanced. Frankly, no-one who had been through what they had been through, and are continuing to go through, could blame them."
Mr Seiger added that the family felt "completely let down and abandoned" over the case, more than 12 weeks the teenager died in a head-on collision.
A CPS spokeswoman said: "We appreciate how difficult this time must be for Harry's loved ones and understand that his family are seeking answers.
"However, whilst the case is under active consideration, we are unable to meet with Harry's family to discuss its progress.
"The CPS is carefully considering all the available information, including the impact on Harry's family, in order to make an independent and objective charging decision.
"Our Chief Crown Prosecutor will meet with Harry's parents as soon as is it possible to provide them with an update."