Updated

A senior detective leading an official inquiry into the death of Princess Diana said Tuesday that new forensic evidence and fresh witnesses have been uncovered by investigators.

Lord John Stevens, the former head of London's Metropolitan Police, refused to elaborate further on the findings of the two-year inquiry into the high-speed car crash in August 1997 in Paris that killed Diana, her boyfriend, Dodi Fayed, and their chauffeur, Henry Paul.

An interim report had been expected to be published this month, but police officials said no date had been set for its release.

Speaking at a literary festival in Hay-on-Wye, Wales, Stevens said his team of 10 detectives had made progress in examining the deaths — and a raft of conspiracy theories that surround the crash.

"We've got new witnesses and new forensic evidence," Stevens said, but refused to confirm if any were eyewitnesses. "I can't tell you at this stage ... you've already got under my radar."

He said his inquiry has looked at a range of theories about the deaths, including an allegation that Prince Charles was plotting to kill his former wife by staging a car accident.