The parents of a young man whose death in a crash sparked an international diplomatic row have dropped their legal action against Northamptonshire Police.
Harry Dunn, 19, was fatally injured outside RAF Croughton in August.
His family began legal action against the force and the Foreign Office after US suspect Anne Sacoolas left the UK, citing diplomatic immunity.
After seeing documents disclosed in the case the family said the “police are absolved of any blame”.
The information provided for the court proceedings showed the force “could have done no more last August and September to ensure that Mrs Sacoolas was brought to justice”, said family spokesman Radd Seiger.
Police had been “kept in the dark” by the FCO (Foreign & Commonwealth Office) about uncertainty relating to Mrs Sacoolas’ immunity status, he said.
Mr Seiger said: “Our case remains that the documents clearly show how the police investigation was effectively stopped in its tracks abruptly when the Foreign Office told the police shortly after Harry died that Mrs Sacoolas had diplomatic immunity.”
Northamptonshire Police previously said it was “not informed” by the FCO of the arrangements that allowed Mrs Sacoolas to claim diplomatic immunity.
A two-day judicial review hearing at the High Court in November is scheduled, with Mr Dunn’s parents, Tim Dunn and Charlotte Charles, claiming the foreign secretary “obstructed justice” by allowing Mrs Sacoolas to leave the UK.
Northamptonshire Police were brought into the legal claim in January.
The force will continue to be involved in the claim as an “interested party”, said Mr Seiger.
In December last year, Mrs Sacoolas was charged with causing death by dangerous driving but an extradition request was rejected by the US.
Earlier this month the UK and US agreed to amend the “anomaly” which allowed Mrs Sacoolas to claim diplomatic immunity.
A Northamptonshire Police spokesman said: “This is an ongoing legal matter and it would therefore be inappropriate to comment further at this time.”
The FCO has been approached for comment.