“What was inside it?” asked Alicia.

“Air,” pronounced Gil de Partera. “Nothing. His booty, or whatever it was he’d hidden there, had disappeared. The Barcelona police were about to arrest him on his way out of the station when Salgado collapsed in the rain. The officers had noticed that when he left the bookshop, two of its employees followed him to the station. Once Salgado lay stretched out on the ground, one of those two employees knelt down beside him for a few seconds and then left. When the policemen reached Salgado, he was already dead. It could be a case of divine justice, the robbed robber and all that, but the autopsy revealed needle marks on his back and on his clothes, and traces of strychnine in his blood.”

“Could it have been the two bookshop employees? The accomplices get rid of their bait once he’s no longer any use to them, or once they realize their safety has been jeopardized because they’re being watched by the police.”

“That was one of the theories, but it was ruled out. In fact, anyone who’d been at the station could have murdered him without Salgado even noticing. The policemen were keeping a close eye on the two bookshop employees and did not see any direct contact between them and Salgado until Salgado collapsed, presumably dead.”

“Could they have administered the poison in the bookshop, before Salgado set off toward the station?” asked Leandro.

This time it was Alicia who replied. “No. Strychnine acts very fast, even more so in an older man, and one whose physical condition had presumably been affected by spending almost twenty years in a dungeon. No more than two minutes would have elapsed between the prick and his death.”

Gil de Partera looked at her, holding back an expression of approval. “That’s right. The most likely explanation is that somebody else was in the station that day, someone who went unnoticed by the police officers and had decided the moment had come to get rid of Salgado.”

“What do we know about these two bookshop employees?”

“One of them is Daniel Sempere, the son of the owner. The other answers to Fermín Romero de Torres, whose trail in the records is confused and shows signs of documentary impersonation. Perhaps to establish a false identity.”

“What was their connection to the case, and what were they doing there?”

“That wasn’t established.”

“And weren’t they questioned?”

Gil de Partera shook his head. “Once again, by express instructions from Minister Valls. Against our own judgment.”

“What about the trail leading to Salgado’s accomplice or accomplices?

“At a standstill.”

“Perhaps the minister will change his mind now and allow you to . . .”

Gil de Partera unearthed his wolfish veteran policeman’s smile.

“That’s what I was coming to. Exactly nine days ago, at daybreak, the day after the masquerade ball organized in his Somosaguas residence, Don Mauricio Valls abandoned his home in a car, accompanied by his chief bodyguard, Vicente Carmona.”