A housekeeper had let me in and left me to talk to him unsupervised. I asked him a few simple questions, which he answered with an air of great courtesy. He looked to me as if he were pretending to be dafter than he was, but most old men enjoy doing that for their private amusement. I was looking forward to doing it myself one day.

I told him,, by way of conversation, that I, had come here from Tibur.

`Did you, see my daughter?'

`I thought your family were in Rome, sir?'

`Oh…' The poor old stick looked confused. `Yes, that may be so. Yes, yes; I do have a daughter in Rome-'

`When did you last' see your daughter, sir?' I deduced he had been abandoned out here for so long he had forgotten what family he had.

`Oh-… I saw her not long ago,' he assured me, though somehow it sounded as if it happened a long time back. He was so vague it could just as, well have been two days- ago. As a witness, the old chap managed to seem wickedly unreliable. His deep-set eyes suggested that he knew it too, and didn't care if he misled me.

`You don't visit Rome a lot, nowadays?'

`Do you know, I'm eighty-six!'

`That's wonderful!' I assured him.' He had already told me twice.

He seemed eager for company, though; he had little of interest to say to anyone. I managed to extricate myself fairly gently. Something about Rosius Gratus suggested he could well be up to mischief, but once I knew he could not be the murderer I needed to be on my way.

I cantered back to the road, this time seeing nobody along the track.

FIFTY ONE

The place where we would be staying lay near the various springs which fed the Aqua Marcia. Bolanus had suggested their underground position would make access for the killer both difficult and unlikely. That was not how the dismembered hands entered the supply.

But Bolanus reckoned he could provide our answer. He and Frontinus were waiting for mews arranged, at the forty-second milestone: beside a large mud reservoir where the Anio Novus began. The valley was full of birdsong. It was a bright country afternoon, in grim contrast to the dark conversations we were about to hold.

A dam with a sluice in the bed of the river helped steer part of the current into this basin. It formed a huge settling tank which filtered out impurities before the start of the aqueduct. Now for the first time in years it had been drained and cleaned out. Banks of dredged-up mud were drying all around it. Slow-moving public slaves were unloading; their breakfast from a donkey, leaving their tools in his pack: a typical scene. The donkey turned his head suddenly and grabbed a bit to eat himself; he knew how to get the better of the water board.

`With aqueducts,' Bolanus explained to us, `it's difficult and unnecessary to design a filtration system along the whole run. We tend to make a big effort at the start, then have extra tanks at the end, just before distribution starts. But that means anything which gets past the first filter can go all the way to Rome.'

`Arriving as little as a day later;' I reminded him, remembering what he had told me in an earlier discussion.

`My star pupil! Anyway, as soon as I came up here I could see we had problems. This basin had never been cleared since Caligula inaugurated the channel. You can imagine what we found in the mud.'

`That was when you uncovered more remains?' Frontinus prompted.

Bolanus looked sick. 'I found a leg.'

'Was that all?' Frontinus and I exchanged a glance. The message that had reached us previously had implied limbs of all sorts and sizes.

'That was enough for me! It was horrendously decayed; we had to bury it.' Bolanus, who had seemed so sanguine, had become appalled now he had actually seen the gruesome relics involved. `I can't describe what it was like clearing out the mud. There were a few loose bones we could not identify.'

A foreman produced them for us. Workmen like to keep a jar of interesting finds. All the better if it includes parts of old skeletons.

`I'll ask somebody who hunts,' suggested Frontinus, ever practical, as he fearlessly handled the pieces of knuckle and leg bone. `But even if we decide they are human, they-won't help identification.'

`No; but these might.' Bolanus himself was unpacking his knapsack.

He produced a small fold of material; it looked, like a napkin from one of his excellent lunch hampers. Carefully unfolding it, he revealed a gold earring. It was of good: work manship, crescent-shaped and covered with handsome granulation, with five dangling chains, each ending in a fine gold ball. Bolanus held it up between his fingers in silence, as if to imagine it hanging gracefully on a female ear.

Accompanying the earring was a string of jewellery, probably part of a longer necklace, since there was no clasp. Bright blue glass beads – lapis, or, something very similar had metal caps which joined them to small squares of delicate patterns cut from sheet gold.

`It's very unusual to find items like this up here,' Bolanus said, `In the sewers, yes. They could have been lost in the street or, anything. Coins and all kinds of gems turn up there – one work gang even discovered half a silver dinner service once,'

`It looks as though somebody threw them into the water to get rid of them,' I said. `What girl goes tripping along a remote riverbank in her big city finery?' My companions were silent, leaving it to me to comment on girls.

Depressed by the conversation, Frontinus walked back towards the river. `Should I- have the bed of the Anio dragged?' he asked glumly as I followed him, sharing his low mood; `I could send my allocation of public slaves; may as well use them for something.'

`In due course, maybe. But for now we should avoid any obvious official activity. Everything should look normal. We don't want to scare off the killer. We need to lure. him out and then grab him.'

`Before he kills again,' Frontinus sighed. `I don't like this, Falco. We must be close to him, now – but it could go badly wrong.'

Bolanus had joined us. For a moment we all watched the water rushing into a diversion pipe that currently fed the aqueduct. I turned round and scanned the woods, almost as if I suspected the killer, might be lurking up there watching us.

`I'll tell you what I think happens,' said Bolanus in a sombre voice. Then he paused

He was upset. The isolated spot had worked on him; in his imagination he was sharing the last moments of the women who had been brought so far from, home to a terrible fate, possibly, killed, mutilated and dismembered very near to where we stood.

I helped him out. `The killer lives somewhere locally. He abducts his victims, in Rome, probably because he is not known there and he hopes he won't be traced. Then he brings them forty miles back here.'

Bolanus found his voice again. `After he has finished whatever he does to these girls, he drives back to Rome to dispose of their heads and torsos in the river and the Cloaca -probably to minimise the chance of anything pointing to him locally. But first he cuts off their limbs and throws them into the river -'

`Why doesn't he just throw all the parts into the Anio, or take everything to Rome?' Frontinus asked.

`I imagine,' I said slowly, `he wants the large pieces as far away as possible because they look like identifiable human remains for longer. So he takes them back to Rome but while he's disposing of them in the sewer or the river he's vulnerable. He wants just a couple of large parcels which will sink out of sight quickly if he's being observed. But he thinks he's safe chucking the smaller limbs away, here because they will quickly deteriorate beyond being recognised. Thrown into the stream, they could be eaten by carrion birds or animals, either here in the hills or down on the Campagna. And anything that went over the cascade at Tibur would be well smashed up.'