The Metropolitan Police team is also in the process of contacting Mohammed Al Fayed, the millionaire father of Dodi Al Fayed, who died with Diana in a car crash in Paris in August 1997, and Scott Baker, a senior judge who presided over the inquest into the Princess of Wales' death.
While police have not commented on the investigation at this stage, a report in the Mirror today quoted sources as saying that they have contacted Prince Charles and Mohamed Al Fayed and Baker.
The team has confirmed over the weekend that it was analysing claims, made in a letter from the family of the estranged wife of a Special Air Services (SAS) sniper, but insists there is as yet no new investigation.
"The Metropolitan Police Service is scoping information that has recently been received in relation to the deaths and assessing its relevance and credibility," police had said in a statement.
Diana, Dodi and chauffeur Henri Paul died after their car crashed in the Alma Tunnel in Paris soon after leaving the city's Ritz Hotel on the morning of August 31, 1997. Diana, mother of Prince William and Harry, was 36 at the time of her death, while Dodi was 42.
Operation Paget- the first police investigation into allegations that the princess and Al Fayed were murdered - had concluded, just like a French investigation in 1999, that driver Henri Paul was drunk and driving at excessive speed. However, murder claims have continued but have never been looked into by the British police.
The latest allegations come from the estranged parents-in-law of 'Soldier N', an SAS soldier. The letter claimed the soldier was the special forces member who was the former housemate of Sergeant Danny Nightingale, who was found guilty of illegally possessing a gun and ammunition.
His estranged wife's parents wrote to the SAS' commanding officer claiming the soldier had told his wife that the unit had "arranged" the princess' death and that this had been "covered up". Scotland Yard detectives have reportedly contacted the former soldier's estranged wife.
"The assessment will be carried out by officers from the specialist crime and operations command. This is not a re-investigation and does not come under Operation Paget.
On April 7, 2008, the (inquest) jury concluded their verdict as 'unlawful killing, grossly negligent driving of the following vehicles and of the Mercedes'," a statement from the probe team said.
Earlier this week, a royal spokesperson had said that there would be no comment from Princess Diana's sons - William and Harry. A spokesman for Al Fayed said he would be "interested in seeing the outcome".