I wondered if Olympe, 15, wore ankle chains and had wanton eyes? My father reckons castanets are always suspect − but most Roman men get excited when talking about foreign female entertainers. My mother points out that it is not necessary to have a big bosom to play the lyre well; in fact the opposite. Too much anatomy gets in the way.

Polycarpus turned up again while I was still pondering. He was clearly drawn by curiosity though he said he needed to explain arrangements for my meals: there were no kitchen staff, so trays would be brought in for my lunch and dinner from a thermopolium. I told him not to bother about lunch as I could never be sure where I would be; for example, one day I would certainly have to go over to the Temple of Ceres to interrogate the runaway slaves. Polycarpus said I could eat dinner in my room, or in the garden if I preferred.

Why no staff? Valerius Aviola had sent the chefs and pot-washers to Campania, ready to look after him in the holiday villa; he borrowed slaves from a friend while he and his bride remained in Rome – a normal kind of favour among the property-owning set. The slaves on loan had gone home that night, so I could assume they were not involved in the murders, though they could have passed details of the silverware to thieves.

‘You definitely saw the borrowed slaves leave?’

‘I counted them out every one. You cannot be too careful.’

Quite. On the same basis, I took a good look at Polycarpus, letting him see me do it. He was the usual − thought himself special, but he was overestimating. Rome was packed with freedmen, some of whom were genuinely talented. Others, like this one, just had big ideas.

He was trying to assess me. I had been introduced by Faustus as ‘a professional investigator who regularly assisted him’. I normally stress my independence, but I had accepted this. I needed validity, the right to give people instructions.

What Polycarpus was seeing was a nearly thirty-year-old woman of spare build and inscrutable expression. I could tell he judged everyone solely by appearance. So many people make that mistake. I look beyond, which is why I am a good informer.

I was quietly dressed, though with coloured hems on my gown and stole. I wore a wedding ring, plus everyday earrings. In working mode, I came with nothing on my belt where leisured matrons carried their manicure sets and keys, but a neat satchel slung across my body, in which I kept a note tablet, small change and a very sharp knife. Dark hair, simply knotted at the nape of my neck. Laced shoes I could walk in. Businesslike, but nothing to attract notice on the street.