British investigators have spent the night using high-tech equipment to map the site where Princess Diana died and to gather information for her inquest.
Several conspiracy theories surround Princess Diana's death
Police photographers and surveyors used laser equipment to scan the Paris tunnel where Diana, Dodi Al Fayed and their driver died in a crash in 1997.
The move followed a request by the coroner who will carry out the inquest.
A computer model of the scene will be created, which police said would "enhance understanding" of the crash.
Met Police officers were on hand to use the laser equipment, Scotland Yard confirmed.
The three-dimensional model will use new technology that was not available at the time of the accident.
Diana, her partner - Mr Al Fayed - and their chauffeur died after their Mercedes crashed in the Pont d'Alma Tunnel after leaving the Ritz Hotel on the morning of 31 August, 1997.
The subsequent investigation concluded that driver Henri Paul had been drinking and was driving at high speed.
But Mr Paul's parents say they are not convinced that the blood sample used to judge his alcohol level was their son's.
They have begun legal action in a French court to clear his name.
An inquest into the Princess's death opened in the UK last year.
However, it was adjourned for the then Scotland Yard Commissioner, Sir John Stevens, to begin an investigation into the accident.
The crash has sparked many conspiracy theories.
Dodi's father, Mohammed Al Fayed, demanded a public inquiry amid claims that Diana believed there was a plot to tamper with the brakes of her car and cause a crash.
Sir John is still technically in charge of the investigation but was not in Paris on Tuesday night for the latest stage in the proceedings, Scotland Yard said.
In April last year he travelled to the French capital to visit the scene of the crash.