He was investigated for corruption
Audio recordings believed to be of former King Corinna Zu Sayn-Wittgenstein-Sayn speaking to a former police chief were leaked to the press in mid-2018. Zayn-Wittgenstein claimed that Juan Carlos had received the post. results from commercial contracts in the Gulf countries especially in the late 2000s construction of the €6.7 billion Haramain high-speed railway in Saudi Arabia and maintaining the obtained this in a bank account in Switzerland.
Swiss authorities began investigating Juan Carlos in March 2020 in connection with a gift of $100 million to Sayn-Wittgenstein in 2012. This donation is related to reimbursement fees charged accusations from Saudi Arabia. A letter written by Juan Carlos to his Swiss lawyers in 2018 stated that the gift was irrevocable, even though he had asked for the money back in 2014.
In June 2020, the prosecutor's office of the Supreme Court of Spain agreed to investigate the supporting role of Juan Carlos in Phase II of the high-speed rail link between Mecca and Medina, to determine the extent of the criminal relevance of the events that took place after his abdication. From 1975 through June 2014, Juan Carlos enjoyed sovereign immunity as the King of Spain and was not subject to legal action.
