'That's what we are here to find out. If it does, we'll be able to match it against Anna Rostova's shoes.'

'The gendarmes will have to catch her first,' Koch objected.

'When they do, I want to be ready,' I stated guardedly. 'I must be sure in my own mind whether she is innocent or guilty before I proceed.'

Lifting down the fascicles from the shelf where Immanuel Kant had left them, I placed them on the table while Koch held up the lantern to a.s.sist me.

'Our job must begin in this room,' I said, splitting the bundle of papers into two roughly equal piles. 'Those are for you to check,' I said, moving the first pile towards Koch. 'These are mine.'

I did not need to encourage him. He shifted a large alidade measuring-instrument out of harm's way and bent over the tabletop in silence, concentrating on the stack of doc.u.ments I had placed in front of him. On the other side of the table, I began to sift through my own portion of the papers, and I was soon equally absorbed in the work. Not least for the meticulous order which Kant had brought to the task. My admiration for his methodology knew no limits. Each item in the first file I examined had been separated from what followed by a sheet of paper which noted the time and the date at which the report had been compiled, together with a short comment regarding the reporter and the weight to be attached to the evidence that he had supplied. The brilliant, organisational nature of Immanuel Kant's mind was precisely reflected in the physical disposition of his papers. The first file consisted of the finding-officers' reports. There was nothing new to me in any of them.

The next bundle was captioned 'Doctor Vigilantius' in Kant's distinctive handwriting. As I digested the first few lines that he had written, every distraction flew from me. It was the original transcript of the necromancer's communication with the departed soul of Jan Konnen: I have been dead for two days now, the sights I've seen grow dim. Be quick for I belong to light no more. Darkness consumes me, my mortal spirit seeping from that perforation...

Clearly, Professor Kant had witnessed a seance like the one I had attended shortly after my arrival in Konigsberg. Were you not impressed by what you saw last night at the Fortress? But what had the philosopher himself been thinking, as he watched Doctor Vigilantius at work? I sought some clue which might reveal his own most private sensations, but no hint was given away. Kant had transcribed the spoken words alone and had left no testimony regarding his intimate impression of their veracity.

I put the first file back on the table and took up a bulkier one. It was marked 'Spatial Characteristics of the Murders in Konigsberg'. As I began to read, my heart tightened in my chest. Who but Immanuel Kant could conceive of a systematic enquiry into murder which might easily have been an additional chapter to the Critique of Pure Reason? Who but Professor Kant could maintain a semblance of calm enquiry when face to face with outrageous facts that would have driven any sane man to quaking terror?

I turned another page and let out a sigh of satisfaction. Drawings of the positions in which all the victims had been found were collected together and catalogued in a portfolio. A connoisseur of prints or a collector of anatomical drawings could have done no better. Professor Kant had inspired the hand of a rough, untaught soldier to replicate the sort of evidence that the untrained police ignored as a rule. The schematic reporting of such invaluable details opened up prospects regarding the nature and execution of crime which no man had ever contemplated before myself. I laid the drawings out on the table in the order in which the murders had taken place, and called for Koch.

'Just look at these,' I said, my voice echoing around the vault.

'What are they, sir?'

'The precise positions in which the bodies were discovered.'

The pencil lines were faint, uncertain. They had been gone over more than once as the amateur sketcher tried to get closer and closer to the horrid truth before his eyes. 'These doodles are Lublinsky's work. Now, let us see if the footprints left in Kant's garden match anything shown here.'

We began to study them together, Koch's intensity matched by my own, glued to those drawings, a.n.a.lysing every line and every mark until our poor eyes ached. But there was nothing to suggest that the sketch I had made the night before was similar to anything that Lublinsky had ever drawn.

'What about these smudges, sir?'

Koch's finger indicated some odd cross-hatchings traced near the body of Jan Konnen. We stared at them for some moments. They might have been marks in the form of a cross like those that I had found in the snow, but the scale was wholly different. I had drawn a shoe in its actual proportions, and nothing else, while Officer Lublinsky had attempted to sketch the entire scene of a murder.

'I don't know, Koch. It could be a cross. Indeed, I am inclined to believe that it is, but it might be something else,' I admitted reluctantly, picking up another sheet of paper. 'We must consider the possibility that the artist was not equal to his task. In trying to represent everything, he may have included too much. Still, this looks like a cross, don't you think?' I indicated the drawing with my finger. 'Officer Lublinsky may have excluded a great deal of vital information in pursuit of what he thought was clarity. Too much, too little? In either case, the drawings are not conclusive.'

'So, until we find Anna Rostova and compare her shoes with the drawing that you made,' Koch concluded, 'we'll never know for sure if it was she who entered Professor Kant's garden, will we, sir?'

The image of Anna Rostova flashed before my eyes. I saw the gendarmes chasing her, catching her, throwing her to the ground, doing her harm. It ought to have been my most fervent wish. Instead, it was my greatest fear. I had let the hounds loose before, and caused unnecessary suffering. Now, I wavered between extremes. If she were the killer, the case would be over, she would be condemned. But what if she were innocent of murder? She would escape execution, but not imprisonment for abortion, and the inevitable abuse of incarceration and forced labour. I hardly knew which I preferred.

'And yet,' I murmured, my eyes nailed to those sketches, 'they were all kneeling. Lublinsky is consistent in that respect. Each one fell down in more or less the same position.'

'Just like Tifferch, sir. He...'

'Herr Tifferch was lying on an anatomic table,' I interrupted. 'He was an isolated object without a context. Concentrate on the drawings, Koch. Here, you see, the victims are located in the real world. This is the world in which the killer moved. I...I had not fully understood the implications before. I had thought it a mere coincidence that they were kneeling...'

I paused, deep in thought.

'Perhaps, is it just a coincidence, sir? The violence of the attack may have knocked them off their feet.'

'Oh, no, Koch. No,' I insisted, shuffling quickly from one drawing to the next, then back again. 'You see? A man struck from behind would fall flat on his face if death were instantaneous, but that was not the case. These people are all kneeling. We have the entire sequence of murders here, as Lublinsky sketched them. It's as if we can see the crimes being committed one after the other. Each victim fell just so, and his or her forehead came to rest against something, a wall, or a bench in the case of Frau Brunner. So why did they not fall flat, Koch?'

'You seem to believe that there is a reason, sir.'

'There is, indeed. Because they were already kneeling when they were struck. That is, they knelt down in front of the killer, then they were despatched.'

Koch looked up and stared at me in wonder.

'But that's impossible, sir! Would any sane person do such a thing? I can't imagine...An execution, sir? As if they were being put to death.'

'Precisely, Koch. An execution. But how did he get them to kneel?'

Koch glanced from one drawing to the next. 'Why didn't Herr Professor Kant point this detail out to you, sir?' he asked. 'He cannot have failed to notice the fact.'

'He has done much more,' I replied vigorously. 'He has placed the evidence before my eyes. Kant made sure that Tifferch's body was preserved under ice and snow for me to see. Then, he made an issue of the fact that Morik's corpse had not been found in the kneeling position. It is not his way to point things out, Koch. He shows you the available data, then he invites you to explain the obvious. I ought to have understood all this before.'

'That's all very well, sir,' Koch objected, 'but Professor Kant had no way of verifying the truth of what Lublinsky had drawn.'

I was silenced for a moment. It was a reasonable objection, after all. But the answer came to me in a flash: 'Tifferch's trousers!' I exclaimed.

'Sir?'

'There we have the proof, Koch. In Tifferch's trousers. The knees of his breeches were caked with mud. Do you remember? If my theory is correct, all the victims' knees should be dirty, if Lublinsky has drawn precisely what he was told to draw.'

I glanced around the room.

'Over there, Koch!' I said, pointing to the upper shelf against the far wall. 'Shift that vacuum pump out of the way, and bring down a box. Any one will do. To verify Lublinsky's evidence, all we have to do is examine the clothing.'

Koch hauled down a long, flat, pressed-paper box, the sort used by tailors to deliver suits and gowns. With mounting excitement we removed the lid. A cloud of dust flew into the air and into our lungs.

'Paula-Anne Brunner,' Koch announced with a splutter. The woman's name was written on a slip of yellow paper listing all the items in the container. I could not fail to recognise Kant's neat handwriting.

A thin, green cloak of braided cotton,' Koch began to read. A long-sleeved white blouse. A grey gown of thin, indeterminate fabric. One pair of heavy, grey woollen stockings. One pair of wooden clogs with worn heels...'

'The gown, Koch.' I interrupted the litany. 'Let's see the gown.'

Koch spread the garment out on the table-top, then stood back. I moved closer and bent over the woman's gown, flipping it over, then turning it back again, my anxiety mounting.

'There are no stains,' I spluttered, the words choking in my throat. 'Not a single spot of mud on the knees.'

Koch's voice was a low murmur close to my ear. 'What does it mean, Herr Stiffeniis?'

'I have no idea,' I admitted, my head spinning with confusion.

'Hold on a moment, sir,' Koch declared with energy.

Without a word of explanation, he picked up the list, read it again, then began to search through the items in the garment-box. I watched in silence, fighting the impulse to stop him, resentful of the rough way he was rummaging among the articles that Professor Kant had so carefully arranged there.

'Now, let me see,' he said quietly, pulling out a pair of woollen stockings. 'Frau Brunner possessed this gown, I presume, and no other. The stuff is thin for the season, which made it precious. If she had to kneel down on the ground, she'd have done what any other lady would. She lifted up her best gown and soiled her stockings. You see, sir?'

There was no hint of triumph in his voice.

Like Doubting Thomas, I stretched out my hand and touched the rough, grey worsted with my fingertips. There were holes in the toes and heels. The stockings had been darned and mended more than once. And on the knees were two large, dark stains.

'She put more trust in those heavy stockings to protect her from the winter,' Koch continued, 'than in the light gown she was wearing.'

'So simple, so logical,' I murmured. And quite conclusive. We may a.s.sume from this that all the victims knelt down voluntarily before the person who intended to butcher them. They seem to have helped the killer.'

The words I had read from Vigilantius's macabre colloquy with Jan Konnen flashed into my mind, and I felt a tingle of excitement. Could there be a grain of truth in what the necromancer called his 'art'?

Darkness surrounded me after I knelt...

'A ritual was being acted out, I'd say, sir. The victims were being sacrificed to some pagan deity, perhaps. This certainly strengthens your case against Anna Rostova,' said Koch excitedly.

I stopped him quickly. 'Put everything back in the folders. Replace those boxes. We still do not know if Anna Rostova really is the killer, but I am pleased to hear that you now appreciate the value of this room and its contents.'

Koch made no reply until he had packed everything away.

'What now, sir?' he asked as he turned to me.

'Let us feast our eyes on the stars!' I said.

'The stars, Herr Stiffeniis?' Koch stared hard at me. 'It isn't lunchtime yet!'

'I have not gone wholly mad,' I explained with a smile. An Italian poet used those very words to describe his escape from h.e.l.l and his safe return to the real world. You and I have been forced underground by this investigation, Koch. First, in the bas.e.m.e.nt of the Fortress with Vigilantius, then in this laboratory. It is time for us to return to the "Realm of Light".'

Outside, sunbeam shafts filtered weakly through a web of gossamer clouds which extended in flimsy strands to the very rim of the earth. Occasional flakes of snow swirled in the air like autumn leaves on the wings of a piercing cold wind. Spread out below us lay the glistening slate roofs and the soaring church spires of Konigsberg. Beyond, the sea stretched to the horizon in thousands of acres of rumpled grey silk. I stood gazing out on the scene for some moments, filling and refilling my lungs with the fresh morning air.

'I need to speak to Lublinsky again,' I said, as we boarded the coach and began to descend the hill in the direction of the centre of town. 'But there is something else that I must do first.'

'What's that, sir?'

'I must call on Professor Kant. We must pay our homage to him, Koch. He needs to know that his faith in me has not been entirely misplaced. I'm afraid that I have not been the best of students.'

Chapter 22.

'Now, let's see who'll be the first. Older does not always mean wiser. Remember that, Hanno! Don't let your brother beat you once again. He has a good head on his small shoulders...'

The images of childhood that remain most clearly fixed in my memory are those a.s.sociated with my father, Wilhelm Ignatius Stiffeniis. A martinet by natural inclination, religious to a fault, our father had no time for indolence or tantrums. But oftentimes, he would amuse himself at the expense of my younger brother and myself with a conundrum of his own devising. As with all the things my father did, there was a serious purpose in his games. He wished to impart a lesson which would serve Stefan and me in our adult lives.

The family house still lies in the drear hill country out beyond Ruisling. A large and rambling mansion, all the rooms were cluttered with knick-knacks. My father would delight in hiding a well-known trifle. Then, he would call us in, and invite us to speculate which object had been shifted from its usual place. Our memories became prodigious as we grew accustomed to cataloguing the entire contents of the house. Indeed, we knew the material and the substance of our inheritance by heart before we were out of the nursery.

'Now, lad, what d'ye have to say for yourself? A curlicue paperweight of French gla.s.s? Bravo, my boy!'

The winner was inevitably rewarded with a slice of brown bread coated thickly with the rich, dark honey from my father's hives. That was the prize. The chestnut-scented honey had brought renown and wealth to the house of Stiffeniis. To Stefan and myself, it represented a sort of condensation of all that our father stood for: the authority which he exercised with knowing severity, the promise that hard work would bear rich fruit, the notion that generosity would inevitably reward the effort required to overcome an arduous test. To taste my father's honey meant admission to his world. It signified his acceptance. And for no other reason than that he had decided that it should be so. The severe glance reserved for the loser was a sufficient punishment in itself. And that severe glance had left its mark on my less than perfect infancy.

Though younger by two years, Stefan was more compet.i.tive than I would ever be. Blessed with a quick intelligence and powers of intense concentration, he was the victor more often than not. And when our father was too occupied with the business of the estate, Stefan threw out challenges of his own, which became ever more physical and daring as we grew. Again invariably, I should say I was the loser. Stefan was taller, Stefan was stronger, Stefan was destined for a brilliant military career. Yet that military career would last less than six months. Father took me aside when his favourite son was brought home in a carriage and told me of the doctor's diagnosis. 'No more games,' he ordered. 'No physical trials of any sort, Hanno. I hold you responsible for your brother's life.'

In a word, he commanded me to treat my brother as an invalid. And so I did until the day that Stefan proposed a challenge that I was unable to refuse.

As the coach trundled slowly on towards Professor Kant's, I began to wonder whether my mentor had been playing his own sly variant of my father's game at my expense. I had the persistent feeling that Kant had been trying to test my abilities, perhaps to gauge how I might react to the provocation. On more than one occasion he had challenged me to reconsider something that I had failed to notice. But why did he wish to measure and probe my investigative capacities? Was he critical of my lack of attention to detail? Or was he more concerned about the superficiality with which I a.n.a.lysed the available evidence?

Just then, the carriage turned the corner at the end of the Castle Walk into Magisterstra.s.se. The cobbled street gave way to pebbles and the horse broke into a liberating trot. Glancing out of the window, I realised with a start that something was not as it ought to be at the house: black smoke was billowing in the wind from the tallest chimney at the gable-end. As I had read with interest in a colourful biographical sketch which had been published in one of the more popular literary magazines, Professor Kant forbade the lighting of fires before noon, both in summer and in winter. And the upstairs curtains were still drawn fast! As the writer had described the facts, Immanuel Kant insisted that they be thrown open with the first light of dawn. 'The slightest change in the mechanical regularity of the Philosopher's daily life', the writer concluded, 'means that something has occurred to prevent it from running its course in the manner which he has set for himself, and that it is a matter of some importance...'

I jumped down from the coach and ran swiftly up the garden path with Sergeant Koch hard on my heels. Before I had touched the knocker, Johannes opened the door. The expression on his face seemed to confirm my worst fears. His eyes flashed with what I took to be fright.

'What's wrong, Johannes?'

'You are very early, Herr Stiffeniis,' he said with a theatrical shake of the head, raising his forefinger to his lips. He nodded over his shoulder, and spoke out far louder than was necessary. 'Professor Kant has not yet donned his periwig.'

Could this simple fact distress the servant so much?

'My master is not yet ready to receive visitors,' Johannes explained, pointedly turning his head towards his master's study as he took my hat and gloves.

'But the fire is lit. I saw the smoke...'

'Professor Kant has a head-cold this morning, sir.'

Beyond Johannes's shoulder, the study-door was ajar. I could see only the writing-table set hard against the wall, an elbow resting on it, and a slippered foot extended beneath. I felt rea.s.sured to know that Kant was safe, out of bed and well enough to sit at his desk, though what he might be doing, I had not the faintest idea.

Following the direction of my glance, Johannes stepped quickly across the hall and gently closed the study door. 'I am attending to him just now, sir.'

'What's going on?' I whispered.

The servant glanced nervously over his shoulder again, then told me something that I would rather not have heard. 'Thank the Lord, he's safe, sir! He had a visitor this night.'

'Explain yourself,' I said sharply.

'I slept in the house, sir, as you ordered,' he continued. 'Professor Kant said he had some work to finish, and could do it all the better if he were left in peace. He asked me if I wished to have an evening free to visit my wife. Of course, I replied that I did not, sir. I informed him that I had much work to do about the house.'

'Thank the Lord, indeed!'

'I have learnt my lesson, sir. I told him that I'd be in the morning room if he needed me. He retired to his study, while I prepared a chair next door. I decided to stay on guard all night, but...' He swallowed a bitter sigh of mortification. 'I must have fallen asleep. Suddenly, something woke me. It was the French window to the garden, sir, I'd swear.'

'At the rear of the house?'

He nodded. 'It makes a creaking noise like no other.'

'What time was this?'

'Not long after midnight, I suppose.'