Princess Diana.Photo: Jayne Fincher/Princess Diana Archive/Getty

Diana, Princess of Wales (1961 - 1997) attends the Armistice Day wreath-laying ceremony at the Arc de Triomphe in Paris, France, 11th November 1988. She is wearing a black coat by Jasper Conran and a hat by Viv Knowland.

Twenty-five years afterPrincess Diana’s death in a Paris car crash, an investigator on the case is speaking out about the incident.

“It’s my absolute total belief it was a terrible, tragic accident in which three people lost their lives and one other person had their life turned upside down,” Douglas said.

Host Ranvir Singh asked if it was the combination of no seatbelts, paparazzi chasing the car and the driver having some drinks.

“When you look at most incidents, accidents, you find there’s a chain of events, and if any one of those chain of events had been different, it might not have led to that happening,” Douglas said. “For example, if they’d been wearing seatbelts, our experts tells us it was probably an 80% chance that they would have survived the accident.”

Prince Charleswasinterviewed as part of the investigationabout a note that Princess Diana wrote to her butler in 1995 which said, “My husband is planning ‘an accident’ in my car, brake failure and serious head injury.”

David Douglas and Lord Stevens in 2006.Scott Barbour/Getty

Senior investigating officer, Detective Chief Superindendent David Douglas (L) and the former Commissioner of London’s Metropolitan Police, Lord Stevens answer reporters' questions during a press conference after an official British police inquiry into the Paris car crash which killed Princess Diana and Dodi Al Fayed on December 14, 2006 in London, England. Lord Stevens, who led the three year investigation found there was no evidence that the couple were murdered. Princess Diana and Dodi Al Fayed died when the car in which they were passengers crashed in the Pont de l’Alma tunnel, Paris in August 1997.

Douglas said of interviewingPrince Charles, “So it’s remarkable… but in actual fact, it was also unremarkable because it was a straightforward witness statement from someone who happened to be the Prince of Wales.”

“When we went in — I’d never met him before obviously — I found him charming,” Douglas said. “He was very polite, friendly. And we sat down — Lord Stevens, Prince of Wales, his private secretary, who was there also. So Michael, Pete, and myself, just the four of us in the room. Lord Stevens obviously took the lead and talked toPrince Charlesabout that note and what became obvious was thatPrince Charlesknew nothing about that note until it became public in 2003. He knew no more than we did.”

Prince Charles and Princess Diana.Tim Graham Photo Library via Getty

Prince Charles And Princess Diana

Princess Diana’s note was written around the time she did her famous BBC Panorama interview with Martin Bashir.

Can’t get enough ofPEOPLE’s Royals coverage?Sign up for our free Royals newsletterto get the latest updates onKate Middleton,Meghan Markleand more!

Flowers outside Kensington Palace after Princess Diana’s death.Liba Taylor/CORBIS/Corbis via Getty

A multi-colored sea of floral tributes to Diana, Princess of Wales, lie outside the gates of her London home. The flowers began to arrive soon after news of Diana’s death, in a Paris car crash, reached Britain.

Lord Stevens regretted that he and his officers did not interview Bashir.

“If there’d been an allegation then that Bashir had produced allegedly fake documents to Princess Diana, which is a criminal offense, we’d have investigated it. My goodness me, we would have done,” Stevens told theDaily Mail. “But this has only come out recently, which is unfortunate.”

source: people.com