Charles Spencer's book on Princess Diana stolen in robbery

Dutch authorities have launched an investigation after multiple copies of Charles Spencer's book about his sister Diana were stolen in a robbery.

The book titled "Swan Song: Diana, My Sister" tells the story about Diana, from his perspective. The books were stolen after robbers targeted a lorry carrying thousands of books.

Four copies of the memoir, concealed in black plastic wrapping to protect their contents, were taken from the vehicle after it had been left overnight during its journey from a Central European printing facility to a distribution warehouse.

The brazen break-in has thrown publication plans into disarray just days before the book's worldwide release.

Last month, Charles Spencer, the brother of Britain's late Princess Diana, promised to divulge the truth about Diana ahead of the 30th anniversary of her ‌death.

Diana, the first wife of King Charles, was killed aged 36 in August 1997 when the car carrying her and her lover Dodi al-Fayed crashed in the Pont de L’Alma tunnel in Paris as it sped away from chasing paparazzi photographers on motorbikes.

"With the 30th anniversary of Diana’s tragic death on the skyline, I’ve been inundated yet again with requests for interviews about my sister," Spencer said in a statement.

"This has convinced me to write down my own thoughts and memories, once and for ‌all, ⁠rather than having the discomfort of again reading the opinions of others, many of which are based on untruths that have become accepted over time."