Camilla Parker Bowles
Camilla Parker Bowles is reportedly afraid that she's going to die next after Princess Diana. Pictured: Camilla visits The International School at ParkCity on Nov. 3, 2017 in Kuala Lumpur, Malaysia. Getty Images/Chris Jackson

Camilla Parker Bowles reportedly feared for her life after Princess Diana's death.

According to Sarah Whalen, author of the upcoming book "Royal Vengeance," Prince Charles' second wife was "terrified" after Princess Diana's fatal car crash. She was afraid that she was going to be murdered and die next.

"After Diana died, her friends reported that Camilla was exceptionally terrified and thought maybe somebody was trying to kill her too," Whalen said during an interview on "Conspiracy" podcast (via Daily Star).

"She may have believed her life was in danger, similar to Diana," the author added. "Camilla had been told by friends that if anything like that ever happens, you are to run away."

Whalen claimed earlier that the late Princess Diana was murdered. The Princess of Wales' death was apparently planned from the start. She was "gravely injured in a deliberate car wreck" and was "allowed to slowly bleed to death."

According to Whalen, the plot was from an "ancient cult ritual." Princess Diana followed into the footsteps of "many royal women," including Henry VIII's wives Anne Boleyn and Catherine Howard.

"English power has always been a combination of battles. This is especially true with women…They engaged in a lot of backstabbing and often suffered execution. There is a very ancient tradition of human sacrifice in England," Whalen wrote in the book. "Diana was plotting a constitutional crisis and she made no attempt to hide it. She was meeting with the press all the time."

Whalen pointed out that Princess Diana had a "series of accidents" prior to the fatal car crash. According to her, those were indications that someone wanted her dead.

There were rumors that the British Secret Intelligence Service caused the accident because Princess Diana's driver was involved with MI6. But some suspected that the royal family was involved too.

According to Princess Diana's former butler, Paul Burrell, the People's Princess suspected that Prince Charles would plot an automobile accident to kill her, so he could marry Camilla. Princess Diana was aware of their affair. However, there was no evidence suggesting that the government and the royals were involved in the accident.

The firefighter who responded to the automobile accident even thought that Princess Diana would survive. According to him, Prince William and Prince Harry's mom was not badly injured compared to the other passengers and there was no blood on her. So it was "upsetting" when he learned that the princess died in the hospital.