We had a short, brisk interview. I asked bluntly if he had wanted to kill his father; he looked amused at the suggestion and denied it. Believing in himself so much, Valerius Simplicianus was unable to imagine his papa ever doing him down − which meant he really did lack motive. His line was, ‘The old man could be annoying, but when all was said and done, we got on fine.’

In other words, since Aviola could not possibly take against such a perfect heir, the heir had no reason to murder his father. Did he?

Weight was against him. His skinny wrists would never manage the steady force needed to strangle someone.

So I asked about his mother and how people were saying she harboured murderous thoughts. To that, Valerius replied in the same languorous, unconcerned tone: ‘Well, the old lady goes off into a world of her own sometimes, but she wouldn’t harm a fly. She’s horribly distressed about what happened − and really you ought not to hound her.’

I said I was sorry if his mother felt hounded. All anybody wanted was to discover the truth about this terrible crime. ‘Me too!’ answered the wonderboy, speaking very earnestly. He had put on his serious face. He leaned towards me and seemed to think he had cleverly deflected my enquiries.

His mother came into the room at that point. There was no point tying to dissect the son while Mama was supervising.

Since the executor, Simplicius, had been keeping quiet about the ex-wife and children when I spoke to him, he had of course misled me on Aviola’s will. I now ascertained from Galla Simplicia that when Simplicius vaguely spoke of ‘a number of bequests to close relatives and old friends’ this included recognition of his three children. Being an effete wastrel, Valerius knew in full what he was due. (They have to. How else will they live? Besides, legacy-hunting is a very Roman occupation.)

He seemed oblivious to the implications of admitting he had known he would come into money when his father died, though I could tell from his mother’s narrow expression that she was well aware it made him a suspect.

I took my leave.

I still had an open mind about Galla Simplicia. I needed evidence. If she had plotted, then let her think she had escaped, while I dug deeper.

I doubted that she killed the couple herself. Strangulation can be a woman’s method, but not when it involves more than one person at a time – well, except when a deranged mother kills all her infant children. Aviola and Mucia together could have driven her off. More importantly, Galla Simplicia did not have the physical strength to have beaten the door porter, Nicostratus. More than one attacker must have taken part, and whoever did it really knew how to inflict fatal damage.