LONDON (AP) – A three-year police inquiry into the death of Princess Diana will issue its long-awaited report Thursday amid hopes it would finally halt the speculation about her fatal Paris car crash in 1997.

John Stevens, the former head of London’s Metropolitan Police, led the investigation of the deaths of Diana, 36, and her companion, Dodi Fayed, 42.

They were killed along with chauffeur Henri Paul when their Mercedes crashed in the Pont d’Alma tunnel in Paris on Aug. 31, 1997, while the couple were being chased by media photographers. Diana’s sons, Prince William and Prince Harry, were briefed on the report’s findings Wednesday, a day before its release to the public, British media said.

The prince’s office would not confirm the reports. Rumors and conspiracy theories continue to swirl around Diana’s death, despite a French judge’s 1999 ruling that the crash was an accident. An investigation later concluded that Paul had been drinking and was driving at high speed.

Stevens and the Metropolitan Police have refused to discuss the findings of his inquiry, although it is widely expected to conclude that Diana’s death was an accident and that Paul was drunk.

But Stevens stoked rumors in January when he said his investigation was “far more complex than any of us thought.” He did not specify what he meant.

The British inquiry, which involved 15 police personnel and is estimated to have cost several million dollars, used cutting-edge computer technology to reconstruct the crash scene and examined the wrecked Mercedes in painstaking detail.

Stevens looked at hundreds of witness statements, traveled to Paris to see the site of the crash, and interviewed Diana’s former husband, Prince Charles.

His report is unlikely to silence the conspiracy theories altogether.

Dodi Fayed’s father, Mohammed al Fayed, claims Diana was pregnant with Dodi’s child and was killed by British intelligence to prevent her embarrassing the royal family.

Al Fayed, who owns London’s famous Harrods department store, has called a news conference for Thursday to respond to Stevens’ report.

On Wednesday, he told NBC’s “Today” show that he would not accept that the deaths were an accident.

“It’s completely outrageous that the leading Scotland Yard officer can come up with such unbelievable judgment,” he said.

The Observer newspaper reported this week that the report also will say U.S. intelligence services were bugging Diana’s phone without the approval of its British counterpart on the night of her death.

The newspaper said U.S. officials had assured Stevens the secretly recorded conversations shed no new light on her death.

The National Security Agency said Tuesday it had never targeted Diana’s communications, but acknowledged it had 39 classified documents containing references to the princess.

The Observer said Stevens’ report would also confirm claims that Paul had been in the pay of the French intelligence services.

The publication of Stevens’ report will allow an inquest into Diana’s death finally to get under way.

The inquest, convened and then swiftly adjourned in 2004, is due to formally resume next year under a retired senior judge, Dame Elizabeth Butler-Sloss. Preliminary hearings will be held Jan. 8-9 at the Royal Courts of Justice.