LONDON — It wasn’t how it was supposed to go. Rather than calming speculation and conspiracy theories about the death of Diana, Princess of Wales, a long-awaited British police inquiry has only fuelled them.

The exhaustive investigation, released yesterday, found that the car crash in a Paris tunnel that killed Diana, 36, and her lover, Dodi Fayed, 42, on a late summer’s night nearly 10 years ago was a “tragic accident.”

“Our conclusion is that, on all the evidence available at this time, there was no conspiracy to murder any of the occupants of the car,” Robert Stevens, who led the inquiry, told reporters at a news conference in London yesterday. “This was a tragic accident.”

“There was no conspiracy or cover-up,” he added, and said his 872-page report did not blame anyone.

As soon as the report was released, online bulletin boards swirled with more questions, theories and counter-theories. Even Lord Stevens, a former commissioner of London’s Metropolitan Police Service, acknowledged the report would not end all the speculation about Diana’s death.

And Mohammed al-Fayed, the main proponent of the theories and father of Dodi, immediately dismissed the findings as a cover-up.

“I am certain, 100 per cent, that a leading member of the Royal Family has planned that, and the whole plot was being executed in his order with the help of members of MI6,” Mr. al-Fayed said after the report came out, referring to Britain’s foreign-intelligence agency.

“It’s just 100-per-cent proof that it is a plan for covering up,” said Mr. al-Fayed, the wealthy owner of the famous Harrod’s department store in London.

“If Dodi and Diana had wed, and if they had had children, Britain would have had, in effect, an alternate royal family. The attractive, personable Fayeds. Or the charmless German Windsors?” he wrote in a column in the Evening Standard newspaper yesterday.

“It was not a situation MI6, with its obsession about militant Islam, could tolerate. And my son, Dodi and Princess Diana paid the price for daring to love each other,” he wrote.

The inquiry examined all the conspiracy theories regarding the crash, which also claimed the life of driver Henri Paul and severely injured bodyguard Trevor Rees-Jones.

Diana and Dodi Fayed were killed just after midnight on Aug. 31, 1997, when Mr. Paul, who was driving their Mercedes Benz S-280 sedan at high speed, lost control and smashed into the 13th median column in the Pont d’Alma road tunnel in Paris. They were trying to evade a group of photographers who had been following them throughout the day.

Lord Stevens dismissed the main theory that Prince Philip, Diana’s former father-in-law, in collusion with Britain’s secret intelligence services, including MI5 and MI6, had Diana killed because of the fear that she had or would become engaged to, and pregnant by, a Muslim.

The report investigated and refuted dozens of other theories.

The three-year investigation, which cost £3.96-million ($8.9-million), interviewed more than 300 witnesses, including two new ones no one had talked to before. Investigators collected more than 600 exhibits and used sophisticated computer modelling to recreate the accident scene.

A poll commissioned by the BBC last week found that a third (31 per cent) of those surveyed believe Diana’s death was not an accident, while 43 per cent believe it was, with the rest unsure.

Diana’s sons, Prince William and Prince Harry, who were briefed personally by Lord Stevens the day before, said they stood by his findings.

The princes “trust that these conclusive findings will end the speculation surrounding the death of their mother Diana, Princess of Wales,” said a statement from Clarence House, the office of Prince Charles.

The publication of the report will allow an inquest into Diana’s death to get under way. The inquest, convened and then swiftly adjourned in 2004, is to resume formally next year under a retired senior judge, Baroness Elizabeth Butler-Sloss. Preliminary hearings will be held Jan. 8 to 9.

The British police inquiry report examines all the allegations of wrongdoing in the deaths of Diana, Princess of Wales, and Dodi Fayed.

Allegation: Mohammed al-Fayed said his son and Diana were involved in a serious relationship and intended to get engaged.

Conclusion: The inquiry found no evidence that Diana was to be engaged or had selected a ring.

Allegation: Mr. al-Fayed alleged Diana was pregnant with his son’s child.

Conclusion: Tests on a blood stain from the carpet of the crashed car, confirmed to be Diana’s, found no evidence of pregnancy, the inquiry said. Only Mr. al-Fayed says Diana told him she was pregnant. There is no other evidence she thought she might be pregnant.

Allegation: Members of the Royal Family, Britain’s domestic intelligence agency MI5, and foreign intelligence agencies were involved the deaths.

Conclusion: The inquiry said Diana’s ex-husband Prince Charles, his father Prince Philip, and Prince William co-operated with the investigation. The inquiry found “no evidence” to support Mr. Fayed’s assertion that Philip was directly involved in a conspiracy to killed the princess. The inquiry quoted some of Diana’s friends as saying she never feared Charles or his entourage. The inquiry categorically dismissed the role of MI5 in Diana’s death. The report said Henri Paul, the driver, was working for the French intelligence as a “low-level informant of sorts.” But it found no evidence to substantiate claims that U.S. intelligence monitored Diana’s telephone calls. The inquiry was not allowed to see 39 files related to Diana held by the National Security Agency, but it quoted the agency’s policy director, Louis Giles, as saying none of the files was relevant to the crash. The report concludes that the spying allegations were “a very difficult thing to prove or disprove.”

Allegation: A white Fiat caused the Mercedes to crash.

Conclusion: There was a glancing contact between the Mercedes and a white Fiat Uno just before the tunnel. It is “very unlikely” that the car will ever be located.

Allegation: Photojournalist James Andanson, who owns a Fiat Uno, committed suicide because of guilt over his involvement in or knowledge of the deaths.

Conclusion: Mr. Andanson, who did own an Uno, was interviewed by French police and was not implicated, said Robert Stevens, who led the inquiry. Mr. Andanson committed suicide in 2000 and his offices were burgled shortly afterward. There was no evidence he was murdered or that he was involved with any security service.

Allegation: Blood samples from Mr. Paul, the driver, were switched to make it appear he was drunk.

Conclusion: The blood samples match Mr. Paul’s DNA, and show that he had three times the legal limit of alcohol in his system at the time of the crash.

Allegation: British authorities have developed a bright flash weapon designed to temporarily blind a driver with the intent of causing a crash, and such a device might have been used.

Conclusion: British authorities do not have such a weapon, and there is no evidence of blinding flashes at the time of the crash.