Ramiro said, ‘Of course I was frustrated. I wished more people had joined in. I wished it had had a greater impact.’

‘So why would you continue with such an ineffectual strategy?’

‘No one had any better ideas.’

‘Apparently someone did,’ Maddalena replied.

Ramiro hummed wearily. ‘Where is this getting you? Is your boss listening in and giving you points for literal-mindedness? No one who spoke to me proposed a better strategy. If you’re going to make me talk for three or four bells at a time, you’ll have to forgive me if some of my statements are made on the understanding that you haven’t ignored everything else I’ve said.’

‘So who was the most frustrated?’ Maddalena pressed him. ‘Even if they didn’t talk about their plans, you must have picked up on their mood.’

‘We were all frustrated. If you want to make a comparative assessment, go and look at the recordings yourself.’

‘People knew when they were on camera,’ Maddalena pointed out. ‘But you were among them when they were less guarded.’

Ramiro couldn’t fault her logic there. He slumped back in his harness, wondering if he was punishing himself for nothing. It was possible that he’d spent time with the bombers without knowing it, and it wasn’t absurd to think that they’d let something slip – some remark that betrayed the degree of their impatience. He wanted the killers caught and punished. If he could give the authorities a genuine clue to their identities, he’d be proud of that.

Off camera, who had ridiculed the strike most vehemently? Placida? Lena? It was hard to put one above the other, but maybe they’d conceived of the bombing together. No doubt they were both already in custody, but with Ramiro’s testimony against them they might buckle and confess.

Maddalena was watching him expectantly. Ramiro felt a cold horror spreading through his gut at the thought of what he’d almost done. The women’s moaning about the strike wasn’t proof of anything, but he couldn’t trust his jailers to accord the observation as little weight as it deserved. Anything he said, however cautiously phrased, could damage two innocent people’s lives irreparably.

‘Analyse the bomb site,’ he said. ‘Find out where the chemicals came from. I want these murderers caught as much as anyone, but I’m not a mind-reader.’

Ramiro woke in the blackness of his cell and shifted on his sand bed. With the walls around him sterilised by the harsh lights of the day cycle, at night there was no trace of moss, leaving a perfect darkness that seemed to stretch out in all directions.