Princess Cristina, daughter of King Juan Carlos of Spain, has been formally declared a suspect in a fraud and money-laundering case that has brought scandal to an already embattled Spanish monarchy.
When she is questioned in court in two months' time, Cristina will become the first direct relative of the King to appear in court since democracy was restored in Spain in the mid-1970s.
But more than that, the case is the latest in a series of damaging headlines that have plunged the Spanish monarchy into crisis and seen public support for the institution drop to its lowest in decades, leading many to question whether it can survive at all.
Cristina, 48, will appear in court on 8 March, to answer allegations that Iñaki Urdangarin, her husband, the Duke of Palma de Mallorca, embezzled millions of euros of public money. She had already been named a suspect in the same case in April last year.
But preliminary charges were dropped after a senior judge - with the support of Spain's anti-corruption authorities and a regional court in Mallorca, where the case is taking place - ruled there was insufficient evidence to implicate her.
In Spain's legal system, being named as a suspect does not in fact mean that actual charges will ever be placed against Cristina, only that some evidence in a case may raise suspicion.
But her forthcoming court appearance, and the damage caused by the four-year-old case, meanwhile, continue to tarnish the monarchy's prestige.
Since 2010 the Duke, a former Olympic handball player, and his one-time business partner Diego Torres have been investigated over allegations of using a not-for-profit foundation, Noos, to syphon off more than €6m of public money from local government contracts for sports and tourism events - with no official bids - in Valencia and the Balearic Islands.
The money was channelled both to offshore bank accounts and Mr Urdangarin's own companies between 2004 and 2006.
Tax authorities have brought no charges against the Princess in relation to the investigation, and Spain's anti-corruption authorities have failed to find evidence against her. And whilst the prosecutor in the case, Pedro Horrach, has asked for a 12-year sentence for Mr Urdangarin, he has maintained the Princess is in the clear.
However, Princess Cristina was a board member of Noos and the co-owner of one company, Aizoon, which is suspected of being used as a front by Mr Urdangarin for money laundering. And now Jose Castro, the judge in charge of the Noos case, believes his nine-month investigation into Cristina’s financial records from the period - which has raked over emails, bank accounts, credit cards and property and tax filings, it is said, in minute detail - has rendered a court appearance by the King’s second daughter necessary.
"We are absolutely convinced of her innocence," Miquel Roca Junyent, one of her lawyers, told Europa Press news agency, whilst admitting that Mr Castro's investigation was much more detailed than that which preceded Cristina's summons in April last year.
The legal request that the Princess, seventh in line to the throne, testify before a judge was lodged in December by a far-right association, Manos Limpias [Clean Hands]. It has a long-standing reputation for legal sniping at establishment personalities, such as the crusading judge Baltasar Garzon, who ordered General Pinochet's arrest in London in 1998.
This development is the latest in a steady drip-feed of lurid newspaper headlines about the Noos and Aizoon cases since 2010, which has severely tarnished the previously squeaky-clean image of Spain's royal family and will render a decline in the monarchy's popularity hard to reverse.
The prolonged royal crisis has reached the point where Rafael Spottorno, the royal household's spokesman, recently described the last three years of pre-trial investigation into the Urdangarin case as "a martyrdom".
Suspending Urdangarin from all royalty-related duties and removing his profile from the royal website (as well as his possibly coincidental disappearance from the royal tableau in Madrid’s biggest waxworks museum) did little to slow the downward trend.
That the monarchy's entanglement in the Noos case has such a power to shock Spanish society is testament to the fact that, for all his playboy reputation, Juan Carlos had long stood above any mudslinging.
That was largely because the Spanish monarch garnered a huge amount of personal respect both for his role in establishing democracy after the death of General Franco in 1975, and for its defence during an attempted coup in 1981.
However, a controversial de luxe hunting trip in the middle of the recession in 2012 - for which he later apologised - went down like a lead balloon amongst cash-strapped Spaniards and suddenly sent the King's popularity into decline.
An opinion poll published on Sunday suggested that nearly two-thirds of Spaniards wanted the 76-year-old to abdicate, up from 45 per cent in 2013.
On Monday, when the frail-looking King, still on crutches and recovering from his latest hip operation, made a poor delivery of his speech at a Christmas holiday celebration, it did little to restore confidence.
The royal household claimed that a lack of light for the stand used for holding papers during his speech had caused the monarch to hesitate. It responded in a similarly low-key fashion to the court's decision regarding Cristina by saying it had "maximum respect for judicial decisions".
That insistence on a sense of "normality", though, gives the impression the royal family are burying their heads in the sand.
But even if the booing and hissing when members of the royal family make public appearances, and calls for the King's abdication, have now become frequent enough to cease to be newsworthy, Juan Carlos seems to have no plans to step down.
"I want to express to you, as King of Spain, my determination to continue the faithful fulfilment of the mandate and the powers attributed to me," the King said in his Christmas Eve address.
The news from a courtroom in Mallorca, however, puts an end to the impression that it is business as usual. The "martyrdom" of Spain's monarchy may be far from over.