Mohamed Al-Fayed has said he still mourns his son Dodi and Princess Diana twenty years after they died and claims they were were killed because they planned to marry.
The doting father, who previously owned Harrods in London's Knightsbridge, spends 300 days a year sitting beside his son's body, which has been interred at a mausoleum in the grounds of his mansion in Barrow Green Court, near Oxted in Surrey, the Daily Mail reports.
He also has left Dodi's Park Lane flat, where he took Diana during the summer of 1997 before the pair died in a car crash, untouched as a shrine to his son.
The billionaire also believes the Princess and Dodi were killed by security services on the order of Prince Philip to prevent her from marrying a Muslim, even though he has no evidence.
One month after the claims were originally made by Mr Fayed in 2000, the upmarket department store was stripped of its 44-year-old royal warrant, which was granted by the Duke of Edinburgh.
A spokesperson at Buckingham Palace said at the time it was due to a "significant decline in the trading relationship" and refused to comment on the matter further.
A close friend told The Sun: "Mohamed believes they were in love and were going to announce their engagement in London the day after the tragedy. He will never get over the death of his son, or that of the Princess - because of the love he had for both."
Another source told the paper: "Mohamed remains confident that information will emerge confirming his belief that Dodi and Diana were deliberately killed by the security services.
"He always says, 'My son was slaughtered', and he believes that was because the Establishment would not allow a Muslim to be married to the woman who would be the mother of the future king."
Despite his claims of a murder plot, an inquest held into the deaths of Dodi and Diana ruled the pair died because of the "grossly negligent" driving of Henri Paul and the paparazzi in pursuit of their car.
Jurors blamed the "unlawful killing" on driver Henri Paul and the group of paparazzi photographers who were following his Mercedes.
Like the earlier French and British police investigations, the panel concluded Mr Paul had been drinking and was speeding when the car hit a pillar in the Alma underpass in Paris in August 1997.
They also singled out the paparazzi's speed and the way they were driving as contributory factors, but concluded the couple could have survived the accident had they been wearing seatbelts.
A Buckingham Palace source said: "The inquest verdict speaks for itself."