Spain’s former Socialist Prime Minister José Luis Rodríguez Zapatero is under formal investigation for alleged influence peddling and related crimes, the country’s top criminal court announced Tuesday. He has been summoned to testify on June 2.

The probe centers on the 2021 bailout of Venezuela-linked airline Plus Ultra, which received a €53 million public loan from a government fund designed to support strategic companies during the COVID-19 pandemic. Zapatero, who left office in 2011, denied any wrongdoing in a Senate hearing in March, stating he “never received any commissions from Plus Ultra.”

The case marks the first time a former Spanish prime minister has been placed under formal investigation since the country returned to democracy after Francisco Franco’s death in 1975.

Opposition parties seized on the news, with the conservative People’s Party demanding urgent explanations from current Prime Minister Pedro Sánchez. The development adds to mounting political pressure on Sánchez, who is already embroiled in other corruption scandals, including the “Koldo case” involving pandemic contract irregularities and an investigation into his wife, Begoña Gómez.