The royal expert, who had claimed that Princess Diana's death was no accident but a murder, has revealed that he has been receiving chilling death threats via phone, owing to his recent revelation.
The author, Brian Watson, said that he was planning on making his theory public when he got a phone call telling him to drop the idea if he valued his family's life, the Daily Star reported.
Earlier, the biographer had decided to make a documentary based on his research, which showed that Diana's assassins had planted a remote control device in her Mercedes, to control the steering of her vehicle and make it crash into a Paris tunnel pillar.
Watson added that as soon as he sent the script of the film 'Who Killed The Queen Of Hearts?' to film studios, he received the deadly threat.