The celebrity photographer, Darren Lions, dubbed "The King of Babarazzi", cast doubt on the official account of the Princess's death in 1997 and likened her death to the assassination of US President John F. Kennedy in 1963.
"People are being assassinated in different ways. I think there are questions that still need to be answered," Lions said in an interview with Australian magazine Ho.
"It's just like the assassination of John Kennedy," he said. "There are a lot of things still pending about his death, whether he was killed by FBI agents or not ... in the opinion that he was killed."
Lions' latest comments came after another interview with the Daily Telegraph, which said the official version of Diana's death was not necessarily the truth.
"Everybody says it's a tragic accident," said Lions, 53. "Some strange things happened that night, and I was part of a lot of strange things that happened that night."
Lions had said in a newspaper article published in August 2017 that he was lucky not to be killed that night as well, adding that he had received death threats while his employees were harassed in the street.
A year-long investigation in Britain has concluded that the Princess of Wales, her Egyptian friend Emad (Dodi) Al Fayed, and driver Henry Paul were killed as a result of a traffic accident caused by the driver's negligence, and blamed the harassment of the paparazzi.
