‘The Praetorians,’ said Silvius, with sly satisfaction, ‘have to remain with the Emperor. The Urban Cohorts are free to roam. Our remit covers major crime—not only in the city, but anywhere within a hundred miles. Because, you see, any horrible criminal activity in that area might affect the sacred capital.’

‘Now it makes sense,’ said Aelianus. Even in the shaky hands of Minas of Karystos he had absorbed enough legal training to care about jurisdictions. ‘For instance, the Modestus case would fall to you?’

‘Yes, but Anacrites wants it.’

‘So?’

‘There is a magistrate at Antium—’

Justinus laughed. ‘The invisible man!’

It was Silvius’ turn to raise an eyebrow.

‘When Modestus and Primilla disappeared, a posse from Antium was sent to investigate. Before Anacrites waded in and stopped our activity, Falco, Petronius and I tried to liaise with the magistrate but he declined to meet us.’

‘You assumed Antium dropped all interest?’ suggested Silvius. ‘No, there is more to the man than that, boys. When he found nothing in the soggy marshes, it’s true he went home and seemed to keep his head down. You may suppose he just spends his life enjoying the sea breezes at Antium, but this togate beach bum has a sense of duty—for civic rectitude, he could be one of our clean-living, right-thinking, porridge-slurping ancestors. Nor does bureaucracy scare him. Amazingly, he went on digging. He looked through records. Then one fine day, he was entertaining the Urban Prefect—our beloved commander, who, it has to be admitted, had gone out to Antium using official expenses in order to scout for a cut-price villa, to keep his bitching wife quiet. Over the men’s sophisticated luncheon, words were exchanged of a diligent nature. Feel free to marvel.’

Aulus leaned in, scooping seafood from a dish. ‘What have they found?’ He had no truck with fancy narratives. Minas probably thought Aulus was not a natural lawyer, but his plain gruffness satisfied me.

‘The magistrate has been following up reports of missing people, people who had disappeared while travelling mainly, so unlikely to have caused a local outcry. A list was prepared. Footmen were sent out into the countryside, some carrying long probes. And they found,’ said Silvius, enjoying the chill he laid on us, ‘two double sets of bodies.’

Aulus dumped a chewed prawn head in an empty saucer. ‘So far.’

Silvius looked at me with only a trace of sarcasm. ‘He catches on!’

‘Thanks. I saved him from ruination: army and the diplomatic—he was a slow slug until I took on his training . . .’ While Aulus seethed mildly, I pressed Silvius, ‘You work outside Rome—so when the Antium big bug talked to the Urban commander, you were assigned to the case?’

‘That’s right. “Liaison officer”. Keeping the locals on track—while letting them believe they have control.’

‘Did you see the bodies yourself?’