ABU DHABI (AFP) - Spain's former king Juan Carlos I was spotted at a tennis tournament in Abu Dhabi on Saturday (Dec 18), days after Swiss prosecutors closed a US$100 million (S$130 million) corruption case against him for lack of evidence.

Juan Carlos was seen by an AFP photographer at a match featuring Spain's Rafael Nadal at the Mubadala exhibition event, a rare public appearance since he went into exile in the United Arab Emirates in August 2020 following graft allegations.

On Monday, Swiss prosecutors said they have closed the case against Juan Carlos over suspicions he received US$100 million in kickbacks for facilitating a high-speed rail contract in Saudi Arabia awarded to a Spanish consortium.

After three years of investigation, the Geneva top prosecutor's office said in a statement that the money transferred into a Swiss bank account had "not been sufficiently documented".

But it said the probe had "not permitted to establish in a sufficient manner a link between the amount received from Saudi Arabia and the contract to build the high-speed train."

Earlier this month Juan Carlos also sought immunity from the English courts after his ex-lover accused him of spying on and harassing her.

Danish businesswoman Corinna zu Sayn-Wittgenstein-Sayn is seeking civil personal injury damages claim against the ex-monarch at the High Court.

But the 83-year-old Juan Carlos, who ruled from 1975 until his abdication in 2014, denies wrongdoing and argues that as a Spanish royal, English courts have no jurisdiction.