Princess Diana conspiracy book claims that the iconic royal kept a secret sex diary and that her car had been "tampered with."

According to the conspiracy book, after the brakes on her Audi soft-top mysterious failed Princess Diana was convinced that her car was sabotaged.

In the new conspiracy book, "The Assassination of Princess Diana," John Morgan claims that the Princess of Wales believed that the incident in west London when her brakes failed was a warning from powerful enemies. The Daily Star reported that Princess Diana referred to these enemies as "the men in grey suits."

According to Morgan's conspiracy book, Princess Diana was afraid that here was a plot to kill her. The book claims that Princess Diana mentioned her fears in notes and phone calls to her lawyers and friends. Princess Diana voiced these fears months before the fatal car accident in Paris.

According to "The Assassination of Princess Diana," the brakes failed on her green Audi in November 1995 while Princess Diana was driving back to Kensington Palace from a doctor's appointment in Marylebone. Princess Diana tried to stop at a traffic light, but the car didn't even slow down. According to the book, Princess Diana called her friend Simone Simmons convinced that someone had tampered with her brakes in an attempt to kill her.

The Princess Diana conspiracy theory book also claimed that Princess Diana kept secret sex diaries and that she was hounded by SAS Snipers.

The Inquisitr recently reported an older Princess Diana conspiracy theory that claimed the SAS shined light in the speeding limosine driver's face in the tunnel in Paris to force a crash.

"The Assassination of Princess Diana" claims Princess Diana believed there was a plot to kill her. Another book called "The Princess Diana Conspiracy" claims that Princess Diana kept a secret sex diary that detailed the royal family's X-rated activities.

Author Alan Power writes: "The dossier she was compiling was powerful stuff. But it also directly endangered the monarchy. It contained what Charles liked in bed, women he had affairs with and what he got up to with Camilla. There are bits about a senior royal and a male servant. The royal was allegedly accused of being discovered in bed with one of his servants."