“What has the investigation yielded so far?” Alicia cut in.

“The investigation concentrated on a series of anonymous letters that Don Mauricio had been receiving for some years and to which he hadn’t attached much importance. Shortly after the failed attack, the minister informed the police of the existence of these threatening letters. The initial investigation revealed that in all likelihood they’d been sent by someone called Sebastián Salgado, a thief and murderer who was serving a sentence in the prison of Montjuïc Castle, in Barcelona, until about two years ago. As you are probably aware, Don Mauricio Valls had been the governor of that prison at the start of his career in the service of the regime, to be precise between 1939 and 1944.”

“Why didn’t he warn the police about the anonymous letters sooner?” asked Alicia.

“As I said, he explained that at first he hadn’t attached much importance to them, although he admitted that perhaps he should have done so. At the time he told us that the tone of the messages was so cryptic that he couldn’t work out their meaning.”

“And what is the tone of these supposed threats?”

“Mostly vague. In the letters the author says that ‘the truth’ cannot be concealed, that ‘the time of justice’ has come for ‘the children of death’ and that ‘he,’ presumably the author, awaits him ‘at the entrance to the labyrinth.’”

“Labyrinth?”

“As I said, the messages are cryptic. They may refer to something that only Valls and whoever wrote them knew about. Although apparently the minister wasn’t able to interpret them either. Maybe they’re the work of a lunatic. We can’t eliminate that possibility.”

“Was Sebastián Salgado already a prisoner in the castle when Valls was appointed governor?”

“Yes. We’ve checked Salgado’s records. In fact, he was sent to the prison in 1939, right after Mauricio Valls was the governor. The minister explained that he remembered him vaguely as being a quarrelsome individual, and this gave credibility to our theory that he was very likely the person who sent the letters.”

“When exactly was he released?”

“Just under two years ago, in fact. Clearly, the dates don’t coincide with the murder attempt in the Círculo de Bellas Artes, or with the earlier ones. Either Salgado worked with someone outside the prison, or he was only being used as a decoy to confuse the trail. This last possibility is becoming more feasible as the investigation advances. As you’ll see in the dossier I’m going to leave with you, the letters were all sent from the post office in Pueblo Seco, Barcelona, where the mail from the inmates of Montjuïc Castle is taken.”

“How do you know which letters stamped in that post office come from the prison and which don’t?”

“All the ones originating from the castle have an identifying stamp affixed to them by the prison office before going into the mail sack.”

“Aren’t the prisoners’ letters checked?”

“Yes, in theory. In practice, as has been confirmed by the very people responsible, only on certain occasions. In any case, nobody was aware that threatening messages to the minister had been detected. It’s also possible that because of the obscure nature of the language used, the prison censors didn’t notice anything relevant.”