‘I presume they escape justice for that,’ I replied bitterly, ‘because the authorities simply think one less villain has to be good news.’

‘Exactly,’ said Faustus. ‘Feuds are common. Retaliation is fast. Bad feeling may simmer for decades, though if an act of violence or vengeance is seen as justified, everyone regards it as fair punishment and quickly forgets.’

‘So as we thought,’ I summed up, ‘given their record for house-breaking, the Rabirius gang might carry out the kind of robbery that supposedly took place here − but even so, they are very unlikely to have killed Valerius Aviola and his wife.’

Both men nodded.

‘One other thing though. What about beating up the porter?’

Faustus seemed prepared for my question. ‘The tribune felt the Rabirii were quite capable of such violence, but they would never inflict it without a good reason. Unless there is something we don’t know, they would have had no social interaction with Aviola, and the porter himself, Nicostratus, would be way below their line of vision.’

‘Did the tribune suggest any other villains who might have robbed the house?’

‘No, he backed Titianus on that. Even if it was a rival gang, the Rabirii would by now have imposed a punishment − and very publicly, to reassert their supremacy.’

I tested another angle: ‘Could they harbour mavericks? Upstarts, who want to challenge the old man?’

‘Olympus, you do like to cover every feasible idea, Albia!’ Faustus in fact looked impressed. ‘It is possible. We were told there is a nephew, Roscius, the youngest of a large brood – brought up a favourite, and now testing his muscle. He specialises in burglary rather than street crime or brothel-mongering. So yes,’ Faustus concluded, ‘this nephew may be changing the pattern. The vigiles view him as the coming man. The tribune does not want to tackle him yet. His policy at present is to let Roscius run, while keeping him under observation. He won’t agree to any premature confrontation.’

‘You respect that view?’ I demanded.

‘I have to. In my role, I must work amicably with other law authorities.’

Justinus was watching us tangle.

‘Of course. So you must.’ I withdrew my objection gracefully. Faustus looked slightly alarmed by the ease with which he brought me round. Justinus hid a chuckle.

The men seemed to have convinced themselves that there was no organised crime involvement. Someone possessed the loot, however, so they had persuaded the Second’s tribune to order further enquiries at places where such silver might be sold on, putting extra pressure on retailers. Although Faustus had pretended to be satisfied that Titianus and his team had looked for the lost wine set at the apartment, he would tomorrow bring men of his own to carry out a discreet new search: a search of this house, plus the adjoining apartments and shops, then extending to the rest of the street if it could be done quietly.