In the years since, her death has been the subject of countless conspiracy theories. Some have falsely claimed that it was not an accident at all, suggesting — without evidence — that the British royal family was involved.

The speculation became so widespread that London’s Metropolitan Police launched Operation Paget to formally investigate the claims. The inquiry concluded there was no evidence of conspiracy, determining that the deaths of Diana and Dodi were the result of a tragic accident.

When asked how he responds to people who still insist on believing otherwise, Dr. Shepherd said bluntly: “I’d just shrug my shoulders and say, ‘Well, you’re wrong.’ You can take 20 facts and knit them into a story if you want, but it doesn’t make it true.”

He continued: “People say, ‘Why was it the 13th pillar in the tunnel?’ Well, that’s random. And if you were part of a so-called ‘Prince Philip Assassination Squad,’ you wouldn’t choose to crash them into the 13th pillar. You’d do something else.”

The pathologist said the theories simply “don’t hold water in the context of what was going on.” He pointed to the established facts: “Henri Paul was drunk, he wasn’t a skilled driver, and he was determined to outrun the paparazzi — possibly with Dodi in the back saying, ‘Just go faster, go faster.’ You can imagine how that situation unfolded. A bad driver, partly drunk, at that speed — it’s not going to end well.”

Reflecting on the experience, Dr. Shepherd said he was acutely aware of the attention surrounding the case. “It was exciting and fascinating to be involved, but I also knew that whatever you said would be challenged by someone. Whatever you said, there’d be a group insisting you were wrong.”

He also shared one haunting detail — that Princess Diana likely would have survived if she had been wearing her seatbelt.

“She might have had a broken rib or a broken arm, but she would have walked away from that crash,” he said. “It was a bad accident, yes, but not unsurvivable. Mercedes cars are designed to absorb that kind of impact. How tragic is that — the one simple click that could have saved her life?”