Diana, Princess of Wales, died 25 years ago after a car crash in the Pont de l’Alma tunnel in Paris. Her death led to a global outpouring of grief and media attention. Much of the public reaction criticised the royal family for what many saw as an unfeeling response to the sudden death of the Prince of Wales’ former wife.

The shock of Diana’s death also sparked countless conspiracy theories. Decades later, many have not given up the idea that Diana may have been the victim of a plot.

Unexpected events, such as deaths or accidents, are fertile breeding ground for conspiracy theories, which allow people to make sense of chaos by finding evidence, coincidences and someone to blame.

Celebrity deaths have inspired an entire genre of conspiracy theories, particularly the death of Princess Diana. While conspiracy theories about Diana’s death may hinge on different, specific details about the circumstances surrounding the fatal crash, many reach the same conclusion – that she was murdered by the royal family or the British authorities.

I study conspiracy theories to find out why people believe in them. One of the questions I ask is about the language of celebrity death conspiracy theories, and why it is so persuasive.

Conspiracy theories are empowering for people, allowing them to become DIY detectives. These “detectives” approach a case having already arrived at their conclusion. In celebrity deaths, this usually means murder by someone who seemingly benefits from the death.

An official inquiry, like Operation Paget, which was set up by the Met police to investigate conspiracy theories about Diana’s death, asks what happened. The conspiracy detective, on the other hand, asks cui bono – who benefits.