London (CNN) -- A newly revealed claim of conspiracy in the death of Princess Diana has royal watchers buzzing once again, nearly 16 years after the woman who would now be a royal grandmother died in a Paris car crash.
But British police seem to be knocking down the claim -- that the British military was involved in the deaths of Diana, her boyfriend and their driver in August 1997.
"This is not a re-investigation," London Metropolitan Police tersely stressed, in a statement that revealed none of what it had been told.
The latest claim appears to have been sent first to military authorities and then to London police by the parents-in-law of a British special forces sniper after his marriage had fallen apart, according to an article on the website of the Sunday People newspaper. It did not offer a source for its reporting.
Sunday People said it had seen a seven-page handwritten letter by the in-laws alleging that the soldier, whom the newspaper did not name, had boasted to his wife that the elite British Special Air Service commando unit was behind the deaths.
The UK Ministry of Defence told CNN only that "this is for Metropolitan Police to investigate."
Military authorities have been aware of the claim since the 2011 court-martial of the soldier's former roommate on weapons charges, Sunday People reported. The unnamed soldier mentioned in the letter was a witness in that case, according to the newspaper.
Neither the Sunday People piece nor an earlier version carried by Press Association offered details of the claimed involvement by soldiers in the deaths.
Diana, 36, and Dodi Fayed, her 42-year-old boyfriend, died when the Mercedes-Benz they were traveling in hit a pillar in the Pont de l'Alma tunnel in Paris in August 1997.
They were being followed at the time by the paparazzi after leaving the Ritz Hotel. Their driver, Henri Paul, was also killed. Investigators concluded that Paul was drunk and driving at high speed. Bodyguard Trevor Rees-Jones was the sole survivor.
The princess left behind her two children, Prince William, whose wife recently gave birth to Diana's first grandchild, and Prince Harry. Some 2.5 billion people around the world watched Diana's funeral.
A British coroner's inquest in 2007 concluded that the deaths were the result of "grossly negligent driving of the following vehicles and of the Mercedes." The inquest found no evidence of murder. A London police spokesman said no new information had been examined since this inquest.
Yet the deaths have always been paired with conspiracy theories accusing British and French intelligence services and members of British royalty of orchestrating Diana's death.
The Daily Mirror reported in 2003 that the Princess of Wales wrote to her former butler Paul Burrell 10 months before she died, saying her life was at its "most dangerous" phase and warning of a plot to tamper with the brakes of her car.
After their deaths, Mohamed al Fayed, Dodi's father, said the couple were planning to announce their engagement and publicly accused Prince Philip, Diana's former father-in-law, of orchestrating the couple's murders. He testified at the 2007 inquest.
A spokesman for al Fayed said Sunday he had no comment at this time but trusts the police will do a thorough investigation.
Diana remains wildly popular in death, and news of the new claim sparked an immediate surge in discussion of her death on news sites and social media.
But many seemed skeptical.
"Is it just me or does it (seem) like a Princess Diana conspiracy hits around this time of year, every year?," Twitter user DMR09 posted.
The rumors come to light weeks before the 16th anniversary of Diana's death, and a little more than a month before the British premier of "Diana," a new movie about the former princess's life.
It's unclear whether these allegations will make it any further than previous claims have. London police seem unlikely to make any big announcements, based on the closing line of their statement.
"Not Prepared to Discuss Further," Scotland Yard said in the statement.
Michael Pearson wrote and reported from Atlanta; Atika Shubert reported from London; CNN's Bharati Naik also contributed to this report.