He sniffed. ‘I thought whoever had it must have no right to it. It was hidden away too carefully. The rest of his stuff didn’t look at all swank. The gem couldn’t be his. So I might as well take it off him, mightn’t I? Just the way,’ he whined, with a new aggression in his tone, ‘you’ve taken it off me.’

‘The difference being,’ I answered quietly, ‘I shall hand it in to the vigiles, so they can find out who really owns it.’

Standing beside me, Heracleides laughed. ‘Anacrites won’t like that!’

He was right. But Anacrites would never know, until there was a good reason for Petronius and me to tell him.

Before I left, I took Heracleides out of hearing of his staff. ‘One last question. Who is so keen to know what goes on in Anacrites’ house?’

‘I don’t know what you mean, Falco.’

‘Pig’s pizzle. Anacrites is supposed to be the Chief Spy—but more observers sneaked in last night than deluded fathers and clever slaves in a Greek farce. What if I float the name Claudius Laeta past you?’

‘Never heard of him.’

‘You’re tiring me out. Anacrites may be simple-minded, but I can spot infiltrators. Admit it; you do the same as Scorpus. You get paid to poke around houses, on likely nights . . . Indiscretions happen at parties. People drink too much, there is unfortunate groping, you overhear talk of an illegal betting syndicate, someone says Domitian Caesar needs a good spank, someone else knows about the Praetor’s nasty habit—’

Heracleides looked wide-eyed. ‘What habit?’

I had started a rumour. Well, it was probably true. ‘Educated guess . . . We can make a deal. You tell me about Laeta, and I’ll make sure you will hear no more about your staff’s pilfering last night?’

‘Can’t help you, honestly. Oh leave it alone, Falco—we’ve got a good racket, and it’s harmless. The hosts can all afford it. And we don’t keep the stuff ourselves.’

‘What racket’s this?’

At once Heracleides regretted the slip. He soon drooped and confessed. ‘We lift a few pretty things that look as if they may have sentimental value. We pass them to our principal. He goes along to the house a few days later. He tells them he has heard on his special grapevine about some property that belongs to them. He thinks he can get it all back, and will retrieve it as a special favour. Of course there is a premium to pay . . . You know.’ I knew all right.

‘So who is this?’ It could not be Laeta. He had more class. Blackmail was his medium, not ransoming heirlooms.

‘Someone I’m not prepared to mess with, Falco.’ Well, the scam was almost irrelevant. I handled property-hostage hustles sometimes, but my present interest was in bigger things.