A Spanish judge has ruled that King Felipe VI's sister, Princess Cristina, and her husband must face fraud charges, opening the way to an unprecedented criminal trial.
Less than a week after Felipe, 46, took the Spanish throne promising an "honest and transparent" monarchy, the ruling refocused attention on a scandal that had blighted the final years of the reign of his 76-year-old father Juan Carlos.
Cristina, 49, who was previously considered untouchable, is accused of complicity in the allegedly dodgy business affairs of her husband, 46-year-old former Olympic handball player Inaki Urdangarin.
Judge Jose Castro's decision to press ahead with charges against the royal couple, among others, is open to appeal, said a written ruling released by the court in Palma de Mallorca.
The result of any appeals will be pivotal.
Anti-corruption prosecutors have previously opposed the judge's decision to name Cristina as a suspect, saying there is insufficient evidence against her.
A final decision on whether to put the suspects on trial will only be taken by the Palma de Mallorca provincial court after considering appeals.
If the investigating judge's findings are upheld, however, Cristina would be the first direct relation of the Spanish monarch to stand in the dock as a criminal defendant.
Castro has delved into allegations that Cristina's husband and a former business partner creamed off €6 million (HK$63 million) in public funds from contracts awarded to a charitable foundation, Noos.
Cristina sat on the board of Noos and Urdangarin was its chairman.
Together with her husband, the princess jointly owned another company, Aizoon, which investigators suspect served as a front for laundering embezzled money.
In February this year, the investigating judge grilled Cristina in a six-hour hearing over accounts indicating the use of money from Aizoon for personal expenses, including work on the couple's Barcelona mansion, said to have cost €6 million, dance lessons and Harry Potter books.
But the princess, a mother of four with a master's degree from New York University, said she had simply trusted her husband and had no knowledge of his business affairs.
Cristina has been sidelined from royal activities since the scandal broke.
She was notably absent from ceremonies marking her brother's ascension to the throne on June 19.
Since Felipe became king, neither Cristina nor her elder sister Elena, 50, form part of the official royal family.
Under Spanish law, the representatives of the crown comprise only the king, his wife, his immediate forebears, his descendants and the crown prince.