LONDON - London's police force said Tuesday that there was "no credible evidence" British special forces were involved in the deaths of Princess Diana and her boyfriend, Dodi Fayed, and that it would not reopen the investigation.

Scotland Yard has been looking into claims that the elite British army unit the Special Air Service had played a role. It conducted a "scoping exercise" to assess the credibility of the information and decided whether it warranted reopening the criminal investigation. Police said they were given unprecedented access to the records of British special forces.

"Every reasonable line of inquiry was objectively pursued in order to fully evaluate any potential evidence," police said in a statement Tuesday. "There is no credible evidence to support a theory that such claims had any basis in fact."

The claims, widely reported in the British media, were made by a former SAS member identified only as Soldier N.

Diana, Fayed, and their driver, Henri Paul, died in a car accident in Paris on Aug. 31, 1997.

A jury for the inquest into the deaths of Diana and Fayed returned a verdict in April 2008 saying that "the people's princess" and her boyfriend were unlawfully killed, saying the car's driver and paparazzi share blame for the deaths.

Simon McKay, a lawyer for Fayed's father, Mohamed al-Fayed, said his client was disappointed by the decision not to reopen the criminal investigation.

The elder Fayed had accused Prince Philip, the queen's husband, of directing a complicated conspiracy that resulted in the couple's car slamming into a concrete pier at high speed in an underpass in Paris.