(CNN) -- A judge subpoenaed the Spanish king's son-in-law Thursday in a corruption case that has drawn increased scrutiny to the royal family.
Inaki Urdangarin, the Duke of Palma de Mallorca, must testify on February 6, a Spanish court said in a statement.
The case, widely reported in Spanish media for weeks, has fueled public criticism of the royal family. Thursday's statement from the Balearic Islands Superior Court of Justice formally named Urdangarin as a defendant, but did not specify charges against him.
According to media reports, authorities have been investigating whether a foundation headed by Urdangarin improperly used public funds.
Mario Pascual Vives, an attorney representing Urdangarin, told reporters Thursday that his client is "absolutely innocent."
Vives said Urdangarin, who lives in Washington, was on a skiing trip in the United States and had not spoken with him about the case since the court's announcement Thursday.
Urdangarin, a former Olympic handball player, married the Spanish king's youngest daughter in 1997.
The corruption allegations have brought increased scrutiny to the monarchy as Spain faces a nationwide economic crisis.
The court's announcement came a day after Spain's royal family publicly revealed its finances for the first time in an effort to boost public confidence and transparency.
An announcement by the royal palace that Urdangarin will not participate in official family activities during the investigation and remarks by King Juan Carlos in his Christmas Eve speech that "justice is equal for everyone" have deflected public criticisms of the royal family, according to Gerardo Correas of the International School of Protocol in Madrid.
A large round of applause greeted the king at an inauguration ceremony for the new legislature earlier this week, Correas said.
But many Spaniards were still buzzing over the political scandal -- with some asking whether other members of the royal family were connected to, or aware of, Urdangarin's business dealings.
"The debate continues in the street and will continue for a long time," Correas said.
CNN's Ana Maria Luengo-Romero and Miguel Angel Antonanzas contributed to this report.