Iñaki Urdangarin, son-in-law of Spain's King Juan Carlos, was named Thursday as a suspect in a judicial probe of a foundation he once headed.

The 43-year-old Urdangarin, who holds the title of Duke of Palma, wed Princess Cristina, the youngest daughter of Juan Carlos and Queen Sofia, in October 1997. The couple and their four children now live in Washington, where the duke is an executive with Spanish telecom giant Telefonica.

The magistrate overseeing the investigation of the non-profit Instituto Noos, Jose Castro, summoned Urdangarin to appear in court on Feb. 6 in Palma, capital of the island of Mallorca.

The duke, who headed Noos until 2006, will become the first member of the Spanish royal family to face questioning by a judge.

Prosecutors suspect Urdangarin and Diego Torres, who succeeded the duke as president of the foundation, established a web of shell corporations to facilitate the diversion of public money going to Instituto Noos.

Judge Castro plans to question Urdangarin about contracts Noos received from the Balearic Islands and Valencia regional governments.

The duke is "absolutely innocent," his attorney and spokesman, Mario Pascual Vives, said after receiving formal notification of the court summons.

Now that he has been officially named as a suspect, the duke can "begin to defend" his honor, Vives said.

Spain's governing Popular Party and main opposition Socialists responded to news of the summons by expressing full respect for the actions of the judiciary.

The royal household announced Dec. 12 that Urdangarin would no longer take part in official activities, citing his less than "exemplary" conduct.

On Wednesday, the palace released a detailed report on the royal family's income, outlays and taxes, fulfilling a pledge for greater transparency.

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