An archive image of Luis Bárcenas at the entrance to his Madrid residence. SAMUEL SÁNCHEZ

Prime Minister Mariano Rajoy is still refusing to mention the name of his party’s former treasurer, at least in public. But he will be aware that among the many beans Luis Bárcenas has yet to spill about the Popular Party’s (PP) finances during his two-decade tenure is what he knows about the Gürtel contracts-for-kickbacks scandal.

The PP’s leadership has been worried since 2009, when allegations were first made that senior PP politicians and officials had taken bribes in return for profitable contracts and building permits in the PP-ruled regions of Madrid, Valencia, Galicia and Castilla y León.

On Thursday, Bárcenas was detained without bail. Knowing now that he has little to lose, party officials will be asking themselves with renewed concern: will he talk?

The government says that Rajoy was in Brussels when he learned, like the rest of Spain, through the media, of Bárcenas’ preventive detention. After the meeting of the European Council in the Belgian capital ended late on Thursday, the prime minister said nothing, smilingly telling journalists, “Let’s talk tomorrow morning.”

Senior PP figures have long admitted, albeit it in private, that Bárcenas will do anything to avoid jail time. In 2009, he claims to have taken nine boxes from his offices at party headquarters in Madrid containing compromising documents. He has let it be known that he knows a great many secrets. He even went so far as to meet with a notary public, in December 2012, when it was learned that he had at least one bank account in Switzerland, containing 16 million euros, to make it clear that he was in possession of handwritten accounts indicating that the PP made cash payments to senior figures each month — the ledgers which were subsequently published by EL PAÍS on January 31.

Bárcenas has let it be known that he knows a great many secrets

Bárcenas has made it clear that he will do anything to protect himself, including incriminating his own party. Some in the PP say the worst is over, and that he cannot do any more damage. But nobody knows what information he really has, and just how far he would go if he genuinely had anything incriminating.

“Bárcenas knows the PP better than anybody and has one of the best lawyers in Spain,” says one senior PP figure. “He felt himself to be powerful, virtually untouchable. And now there he is in prison, something that as he himself admitted he has never been able to accept. He could do anything.”

Others in the PP are more sanguine about Bárcenas’ incarceration, saying that whatever the risks, it is the best outcome, and certainly the one that the Attorney General’s Office, which is clearly associated with the government, wanted.

“Now we can tell our supporters and voters that this scoundrel is in jail, and that the Attorney General’s Office backs the decision,” says another senior figure in the PP. “A lot of our people have been looking forward to this moment.”

“I’m happy about it: perhaps he’ll stop laughing at us all now, and if he has something to say, then let him say it," says another.

He felt powerful. And now there he is in jail. He could do anything”

“We needed some kind of example to be set: jail without bail, that’s the only way that the public was going to be satisfied,” adds another.

Regional leaders have been particularly concerned about the impact of the Bárcenas case on their chances of re-election next year, and have been calling for the party’s former treasurer to be locked up. “This person will pay for what he has done, I am convinced,” said Alberto Núñez Feijóo, the head of the regional government of Galicia, earlier this week.

“The grassroots are absolutely disgusted,” said Arantza Quiroga, the head of the PP in the Basque Country. The party’s national leadership, which kept Bárcenas on the payroll until January 31, has been more cautious, in part blaming the media and opposition of stirring up hostility against the PP.

“Even if he does talk, it might end up being better for us: let it all come out, and then we can get on with other things,” says a senior figure. Like many in the party, he says the constant threat hanging over the PP is taking its toll. On Thursday evening, after the news broke, in some circles there was a desire for Bárcenas to talk once and for all, whatever the consequences.

Officially, the PP maintained its silence over Bárcenas, aside from a 17-word press release on Thursday night that failed to mention the disgraced former treasurer, instead saying that it “respects” the decision of the courts. Justice Minister Alberto Ruiz-Gallardón told journalists that “Nobody, either in the PP, or in Spain, could be against the investigation into any matter that the courts deem worthy of investigation.”

Some within the party are angry that neither Ruiz-Gallardón nor Interior Minister Jorge Fernández Díaz have been able to manage the Attorney General’s Office or the police to limit the damage to the party from the Gürtel case. But the anger is directed more at the investigation into the accounts that Bárcenas alleges show under-the-counter payments to senior PP figures than toward Bárcenas himself, who now finds himself without a friend in the party after the discovery that he had amassed a huge fortune, something that senior figures say nobody knew anything about.

The PP says Bárcenas lied to the party, including Rajoy, who said in 2009: “I do not believe that anybody can show that Bárcenas is not innocent.”

Bárcenas must weigh his options inside a prison cell, and only he knows what this latest twist will bring.