New Zealand police are to re-examine a teenager's plot to kill Queen Elizabeth II during her 1981 visit to the country after secret documents confirmed the assassination attempt.
A senior officer will lead the examination of the case file after declassified papers shed new light on the failed efforts of Christopher John Lewis to shoot the Queen as her limousine passed through Dunedin on October 14 1981.
The move comes after the New Zealand establishment faced renewed accusations they attempted to cover up the incident at the time.
The attempt by Lewis, who was then aged 17, to gun down the Queen has featured in a book and newspaper articles but documents obtained by the New Zealand news website Stuff confirm police officers and members of the public heard "what they took to be a shot".
The documents were released under an Official Information Act request to the Commonwealth country's Security Intelligence Service (SIS).
An SIS document said the possibility of a firearm being discharged in the vicinity of the Queen was highly likely and a .22 rifle, with a discharged cartridge in the breech, was recovered by police from the fifth floor of the building Lewis had chosen.
The angle of fire would have made it difficult to hit the Queen as buildings screened her from view, although she was visible briefly on four occasions, the papers stated.
After a former Dunedin detective went public about the assassination attempt in 1997, an SIS memo from the same year stated Lewis had intended to assassinate the Queen but did not have the equipment or vantage point to carry out the attack.
At the time, the incident was played down by New Zealand police, who reportedly told local and international media the apparent sound of a gunshot was a council sign falling over.
Lewis, who died in 1997, was not charged with treason or attempted treason, which added to suspicions of a cover-up, but was convicted of a much lesser offence.
A New Zealand police spokeswoman said: "Given the interest in this historic matter, the police commissioner Mike Bush has asked the deputy commissioner national operations Mike Clement to oversee an examination by current investigation staff of the relevant case file.
"Given the passage of time, it is anticipated this examination of the old file and its associated material will take some time. New Zealand police will share the outcome of this examination once it has been completed."