MADRID (AP) — A Spanish court ruled Thursday that a former head of Mexico’s state oil company must remain in custody while an extradition case is heard against him.

A judge ruled that Emilio Lozoya is a flight risk, according to a statement from the National Court in Madrid.

Mexico issued international arrest warrants against Lozoya last year as a result of corruption investigations. Lozoya has denied wrongdoing.

When he was arrested Wednesday in the southeastern Spanish port of Malaga, Lozoya had a driving license bearing his photograph but a different name, according to the court statement. The judge took that as an attempt to evade justice.

Spanish authorities said Lozoya had entered Spain two days earlier, but a search had been on for him throughout Europe since May.

He is one of the most high-profile detentions for alleged corruption under Mexico’s current president, President Andrés Manuel López Obrador, who has vowed to crack down on graft.

Lozoya was the director of Pemex between 2012 and 2016, during the administration of former President Enrique Peña Nieto. He had also been a key member of Peña Nieto’s presidential campaign.

Last year, López Obrador’s administration issued a number of orders for his arrest. One tied him to the bribery scandal of Brazilian construction behemoth Odebrecht and another to the sale of a fertilizer plant to Pemex at allegedly inflated prices.

The Spanish judge’s ruling referenced an “elaborate scheme” to use resources of illegal origin and participation in acts of corruption “tied to the offer of illegal contracts to his favor on the part of Pemex in exchange for a property.”

The Spanish government, citing Mexico’s Attorney General’s Office, said Lozoya allegedly defrauded the government of $280 million.

The arrest was heralded as a clear win for López Obrador, who has made eradicating corruption the central pillar of his administration.

The president said Thursday at his morning press conference that investigators “must get to the bottom” of the case to hold all those involved responsible.

“There isn’t protection for anyone,” he said. “We proposed ending corruption and that is what we are doing. We’re not going to let anything go, zero corruption, zero impunity.”