We went north for ten miles. With only another two or three to go, we reached the tombs among the stone pines that line the approach to Rome’s Twelfth District. On a bright and baking afternoon this sometimes lonesome vicinity made for good travelling. We hit shade. I was cheerful; I could detect the smell of home and the donkey could sniff her stable. Albia just snuffled miserably but soon I could hand her over to Helena.

Then we ran into the vigiles. Since the Twelfth is looked after by the Fourth Cohort, these were a section of Petro’s men.

Outside the city boundary, discipline evaporated. Some, inevitably, were lying under pine trees for a nap. However, others applied themselves fairly well. They told me they were on the case Petronius had told me about: the corpse dumped in a mausoleum. One ritual laying-out was not enough for Petro. Armed with crowbars and a love of violence, his troops were bashing open mausoleums and peering inside for other bodies that ought not to be there. In the crumbly roadside necropolis, many tombs were so ancient nobody knew who built them. They were easy to search, once the vigiles scraped the sleeping vagrants off their worn old entrance steps. Others, even the oldest, were still used by families; thanks to good diet and our nation’s virility, some Roman clans had long pedigrees.

One cranky owner must have stipulated he had to be present; I saw Tiberius Fusculus, Petro’s trusty, hiding his impatience while the blighted toff fumbled interminably with a padlock. I pulled up the cart and when Fusculus was free again, he strolled over. He was overweight, hot and red-faced. Albia gave him a drink of water. ‘Take it all. Who cares?’ She dispensed her generosity with airy fatalism, as if she herself did not care if she died of thirst.

Avoiding Albia’s aggression like a wise man, Fusculus told me that no more corpses had been found. ‘Well, plenty—’ Fusculus joked, ‘—but none we link to the case.’

‘Will Petronius pull you off it soon?’

‘Not yet, Falco. Obstinate beggar is convinced we have turned up a ritual killer.’

‘Then Petronius Longus must sit it out until the next new moon, or there’s a “rho” in the month, or the red tunic comes home from the laundry—whatever weird trigger tells this killer it’s time for him to shed more gore.’

‘Normally,’ Fusculus agreed, ‘the boss would be happy to lie low. Especially in summer when he likes to get home early to your revered sister and have a nap on their nice sun terrace.’

I was amused. Petro had his eccentric side; he never liked anybody knowing his habits and he had not even told his men that he was living with Maia. They all knew of course. ‘What’s different?’ I asked.

‘Sealed lips. State secret.’

‘Very grown-up! And are you going to share it?’