As Diop understood it, most of these individuals were respectable middle-class citizens – doctors, businessmen, accountants – seeking to escape the turmoil of war and persecution in Iraq, Syria, Somalia, even Pakistan, by buying themselves a new life in Europe. Sometimes they brought their families with them, although only the wealthiest could afford to do so since the Serbians charged $50,000 per head to move illegal immigrants through Serbia and on to France, and did not offer discounts for bulk. Another arm of the operation worked with poorer cargo, the kind that was transported like cattle in the backs of trucks, there to live or die according to the vagaries of heat and cold, and the relative availability of essentials such as food, water, and oxygen. Baba Diop preferred not to involve himself in that kind of haulage. He found it depressing, and incompatible with his Christianity.

As for the two men killed at Gare de Lyon, Diop informed the police that he had been ignorant of their terrorist backgrounds. His policy had always been to ask as few questions as possible. He trusted Marković to share with him all the necessary facets of an operation; anything more, Baba Diop was better off not knowing. Yes, he was aware of the Vuksans, but only peripherally through Marković, because he had never met the brothers himself. He thought that Fouad Belkacem, his colleague who had also been present at Gare de Lyon on that fateful afternoon, might have had some dealings with the Vuksans directly, but he could not be sure. He and Fouad did not talk very much, Diop told the police solemnly. They had little in common, Fouad being a Muslim, a drinker, a smoker, and a fornicator, while Baba Diop was none of these things.

Oh, and Fouad was also apparently a traitor. He had betrayed Baba Diop, Aleksej Marković, and the two Syrians, which meant that Baba, the police stressed, should feel under no obligation to withhold information in order to protect him. Fouad was one of their assets, and had already told them a great deal. Baba Diop’s testimony was required only to corroborate certain details, they said, but he should be careful not to lie because, thanks to Fouad, they would know if he was dissembling, and would punish him accordingly.

But Baba Diop did not believe all of this. He had served for a number of years with the Senegalese National Gendarmerie before his arrest for gross corruption – the reason for that involuntary three-year stay at Rebeuss – and had participated in his share of interrogations. He suspected that whatever information the French might have got out of Fouad Belkacem, it had not been enough to satisfy their curiosity.