Nevertheless, it is always worth pressing the questions. `Were you happy together?'

`Of course we were. Ask anyone!' She may not have realised, I would do just that.

We shepherded the voluptuous Vibia to one side of the grand hall, out of earshot of the slaves who were still being processed. Her glance flickered over them anxiously, yet she made no attempt to intervene; as their mistress she would have been entitled to sit in on the questioning.

`Nice place!' commented Fusculus. Apparently this was his method of setting a wealthy householder's widow at her ease.

It worked. Vibia paid no more attention to the interrogated slaves. `This is our Corinthian Oecus.'

`Very nice!' He smirked. `Is that some Greek sort of thing?'

`Only in the best kind of houses.'

`But Greek?' insisted Fusculus.

He achieved his answer the second time: `My husband's family came from Athens originally.'

`Was that recent?'

`This generation. But they are, perfectly Romanised.' She, I reckoned, came straight off a true Roman trash-heap – though it might have social pretensions.

Fusculus managed not to sneer. Well, not at this stage. It was plain what he thought, and how raucous the conversation would be when the vigiles talked Vibia Merulla over later in the day.

Passus had found her a stool, so we could fuss round, ending up as if by accident in a group looming over her.

`We are very sorry for your loss.' I was examining the lady for signs of genuine grief, she knew that. She looked pale. The kohl-etched eyes were perfect and unsmudged. If she had wept, she had been neatly and expertly mopped up; still, there would be maids here employed specifically to keep her looking presentable, even in the present circumstances.

She produced a wail: `It's horrible! Just horrible -'

`Chin up, darling,' soothed Passus. He was cruder than Fusculus. She looked annoyed, but women who carry a hint of the fish market yet lacquer themselves so expensively have to expect to be patronised.

I addressed her like a kind uncle, though I would have dumped responsibility for any niece like this. `Forgive me for distressing you, but if we are to catch your poor husband's killer we must ascertain the full course of events today.' There were blood and oilstains on the glittering hem of her full-skirted gown, on her narrow-strapped, white leather sandals, and on the perfectly-trimmed toes visible through the dainty straps. `You must have run in to the body when the alarm was raised?' I had let her see me inspecting her feet for evidence. Instinctively, she drew them back beneath her gown. A modest move. Embarrassed, perhaps, that they were no longer quite clean.

`I did,' she said, though for a second I thought she had to think about it.

`What you found must have been a terrible shock. I am sorry to have to remind you, but I need to be quite clear what happened next. You told us you ran into the street screaming – was that immediately after you saw what had happened?'

Vibia gazed at me. `Do you imagine I sat down and polished my nails first?'

Her tone was fairly level. It was impossible to tell whether this was a straightforward sarcastic reaction from a wife irritated by officialdom, or the kind of fighting rejoinder I had sometimes met from culprits defending themselves.

`Why did you run outside?' I continued patiently.

`I thought whoever killed my husband might still be on the premises. I rushed out and screamed and screamed for help.'

`Excuse me, but you do have a large staff here. Were you not confident that they would protect you?' I wondered whether she was unpopular with the household slaves.

For half a breath, she did not answer. Even when she spoke, it avoided the question. `I just wanted to get away from that horrible sight.'

`I have to ask – did it cross your mind that one of the slaves might have done it?'

`Nothing crossed my mind. I did not think.'

`Oh, quite understandable,' I assured her gently. At least this made a change from the frequent scenario where a guilty wife blames a slave to cover herself. `Do you mind if I ask, what had you been doing that morning?'

`I was with my maids.'

And a mirror. And a shopful of glass powder containers. It must have taken some time just to assemble the jewellery collection, dominated by a clanking strand of gold half moons and by earrings so heavy with hard gemstones they must be torture on her lobes. You wouldn't nibble those ears. You might put an eye out, if madam tossed her head and the bank-breaking bijoux swung your way unexpectedly.

`Where's your room, lass?' growled Passus.

`On the second floor.'

`Same as your husband?' he demanded intrusively.

Vibia looked him straight in the eye. `We are a devoted couple,' she reminded him.

`Oh, of course,' Passus returned, still being offensive as he pretended to apologise. `But we see some terrible things in the vigiles. Some of the places we go, the first thing I'd be looking at was whether, while the husband was scribbling in his Greek library, there was a boyfriend creeping up a back stairway to visit the pretty young wife.'

Vibia Merulla seethed in silence. She may have coloured up. Under the layers of sheep-fat foundation, ochre rouge and foam of red nitre face powder, it was difficult to distinguish real effects of flesh and blood.

I took over again: `Would you have any idea what your husband's movements were today?'

`The same as usual. He was a businessman; you must know that. He attended to his business.'

`That's rather vague, you know.' She ignored my mild reproof. Next time I would be rude like Passus. `Part of the time he was in the scriptorium, streetside. I know that, Vibia. Then, I'm told, he came into the library. To read for his own pleasure?'

`What?'

`Reading,' I said. `You know: words written on scrolls. Expressions of thought; depictions of action; inspiration and uplift – or for a publisher, the means to cash.' She looked offended again. Still, I knew her type; she thought plays were where you went to flirt with your girlfriends' husbands and poems were junk verses sent to you in secret packs of sweets by oily gigolos. `He was working?' I insisted.

`Of course.'

`At what?'

`How should I know? Skipping through manuscripts, probably. We would go in and find him, scowling and grumbling – he has a stable of writers he encourages, but frankly, he does not think much of most of them.' Like the slave with the lunch tray, she still slipped into speaking as if the man were alive.

`Could you, or someone on your staff, give me these writers' names?'

`Ask Euschemon. He is -'

`Thanks. I know Euschemon. He is waiting to be interviewed.' Did a flicker of nervousness cross the lady's face? `And did Chrysippus work on manuscripts in his Greek library like that every day?' I asked, trying to ascertain if a murderer could have planned on finding him there.

`If he was at home. He had numerous interests. He was a man of affairs. Some mornings he would be out, seeing clients or other people.'

`Where did he go?'

`The Forum, maybe.'

`Do you know anything about his clients?'

`I am afraid not.' She looked straight back at me. Was it a challenge? `Do you know if he had any enemies?'

'Oh no. He was a much loved and respected man.'

Dear gods. Why do they never realise that informers and the vigiles have heard that claim a hundred lying times before? I managed not to look at Fusculus and Passus, lest we all three collapsed with sidesplitting ridicule.

I folded my arms.

`So. You and Chrysippus lived here, blissfully married.' No reaction from the lady. Still, women rarely come straight out with complaints about men's habits at table or their mean dress allowances, not to a stranger. Well, not a stranger who has just seen the husband of the moment lying nastily dead. Women are less stupid than some investigators make out.