princess diana
Britain's Princess of Wales arrives at her London health club. Johnny Eggitt/AFP/Getty Images)

The royal family was petrified after Princess Diana’s intimate tapes reportedly got lost. The so-called box of secrets was found by Lady Sarah McCorquodale, and she reportedly gave it to Princess Diana’s former royal butler, Paul Burrell, six months after the late royal’s death.

In “Diana: Case Solved,” former detectives and authors Dylan Howard and Colin McLaren said that Princess Diana recorded multiple tapes but only six were released and used in a controversial documentary.

“As far-fetched as it sounds, the claims were central to the 2008 inquest into her death when her sister, Lady Sarah McCorquodale, strenuously denied she destroyed the box of secrets,” the authors said.

When McCorquodale was asked why she passed on the tapes to Burrell, she said that she trusted the former royal butler back then. The two decided to hide the information they saw in inside the box because it contained sensitive information.

The authors also claimed that Princess Diana recorded not just 16 videos with her former voice coach, Peter Settelen in 1993. The late royal also has 12 other tapes that contained her most intimate secrets and no one knows where they are now.

“The royal family was said to be 'petrified' Paul would reveal the allegations squirreled away on tape recordings. The royals knew she had been collecting information on them for years, and wanted her out of the way. They couldn't have had their trail of affairs and seedy secrets coming out in the open,” the authors said.

In 2001, police raided Burrell’s house to find the secret tapes, but they didn’t find them.

“As everyone knows, the Queen herself stepped in at the eleventh hour to state she had suddenly recalled giving Burrell permission to take keepsakes from Diana's apartment – something Burrell had claimed all along,” the book says.

Princess Diana passed away on Aug. 31, 1997, following a fatal car crash in Paris.