“His shoes match the size of the boot-prints you found. And I'd say he took with him a pair of rough foot-wear-there are signs of dirt-clots, but no soles to match.”

He grunted, concentrating on the shelves, and I reluctantly stepped inside. The room smelt of incense, but under the sweetness lay an unpleasant air, as if some small carrion-eater had taken up residence under the settee. I ran my eyes over the spines of those books shelved nearest the lamp: a pamphlet on “Blood Cults of Kerala”; a Sixteenth-Century Inquisitor's manifesto on witchcraft; several books with Chinese writing on the spines. On the next shelf up resided a family of skulls, four of them, in descending height, elaborately engraved with designs.

Holmes came to the desk with an armload of books.

“What have you found?” I asked.

What he had found were three copies of Testimony. He dropped them onto the desk litter and opened the first to the frontispiece: the usual figure, followed by a numeral written in a dry brown ink, its rough outlines suggesting a nib other than metal:

“Six? Oh, sweet God, six? Is that-” My head filled with a rushing noise. I sat down.

“Blood,” he said. “Yes. Although it may as well be that of a sheep rather than a human being.” The words were dispassionate, almost academic: The iron control in his voice said something else entirely.

“Still.” I realised that I was sitting in Brothers' chair and stood up hastily, while Holmes opened the other two copies. One had a 7, although its brown colour was nearly obscured by the blotting sand stuck to it; the next, with an 8, looked like the others I had seen.

“The Adlers' copy,” I said abruptly. “That smear on its title page is actually the numeral one.”

Holmes left the three books open under the desk lamp and went back to the shelf. “The binder told you he made eight?”

I forced my mind to his question. “Brothers seems to like the number eight-eight books, eight sections in each of the four chapters of the book. It would suggest that he has given away three others.” Millicent Dunworthy possessed number two, but I thought I could identify the other Inner Circle members who had received three, four, and five: the nurse, her brother, and the sharp-nosed woman.

“It would also suggest that he took his Book of Truth with him,” Holmes said. “Here's his blotting sand.” He pulled the top off of a surprisingly large decorative tin, and picked up a pencil to stir its contents.

“What a lot,” I said-there must have been a pound of the stuff, easily. I had seen blotting sand used at a solicitor's office, but it was generally a small sifting, easily dusted away. I reached out and took a pinch from the tin, rubbing it through my fingers. Blotting sand. And all those blank pages that wanted filling.

“Holmes-the sand. You found too much. Far more than he would need for just one numeral. And the repeated quill-sharpenings. The Book of Truth is his journal. He's setting down an account of the killings, then and there.”

Holmes looked at the sand, and murmured, “‘It will have blood, they say; blood will have blood.’”

The power of the stuff in our veins: Professor Ledger had told me, and I had not taken it far enough. I had failed to imagine how full-blown the man's madness might be.

At least, I thought, grasping for some relief-at least this was not Damian Adler's madness. Although, even now I had to admit there was nothing to guarantee that Damian was not one of Brothers' acolytes. Nothing, that is, but the impossibility of his participation in the murder of Yolanda Adler, beloved wife, mother of his child.

“However,” Holmes said, bent over the books with his strong glass, “I should have said this number seven has used some material other than blotting sand.”

I took a look, and agreed: The material used to blot this number was fine enough that much of it had stuck. What that meant, if anything, there was no telling.

We replaced the copies of Testimony on the shelf, and while Holmes turned his attention to the walls, I settled to the desk (carrying over a stool, rather than sit again in Brothers' chair). The surface was covered in notes, books, pamphlets, and well-marked guidebooks to Scandinavia, Germany, and Great Britain. I found a desk-diary, which told us that Brothers had been away for the first three weeks of May, and a pamphlet extolling the charms of Bergen, Norway.

His current project, Text of Lights, took up most of the desk, in the form of notes made by a tight hand in a pen that leaked, typescript pages with cross-hatchings and notes, and the occasional torn-out page of a book or magazine with a paragraph circled. This would be Testimony for the masses, with simpler language, lots of Biblical references, astrological details, and concrete examples of the miraculous side-effects of becoming a Child of Lights.

I fished three crumpled sheets from the waste-paper basket, ironing them out with the side of my hand, but found they were only notes he had transferred to the typescript, and in one case, a fresh note spoilt by a gout of ink. I studied the smear, then searched through the debris for the pen that I had spotted, finding it under a discussion of astrological birth-charts. It was an ornate instrument with a twenty-four-karat gold nib, but ink clotted the lower edge of its barrel.

I said to Holmes, “Did you agree that the stain on Yolanda Adler's fingers looked like ink?”

“I did.”

“Because it's possible she wrote that final letter to Damian at this desk, with this pen.” I showed him; he said nothing, just turned his attention to the wall safe that he had found beneath a painting of Stonehenge under a full moon (amateurish and melodramatic and markedly not by Damian Adler).

I opened the desk's upper drawers and found, among the discarded pens, stationery, and paper clips, a wooden box containing half a dozen of the heavy, crude gold rings worn by the Inner Circle, in various sizes. Despite their solid appearance, they felt like gold plate. The next drawer down held maps of England, Scotland, Iceland, Germany, and all of the Scandinavian countries.

The bottom drawer held an assortment of rubbish, including a dog's collar that had clearly been buried for years, a pair of new-looking leather bedroom slippers, and a pretty little dollies' tea-cup.

I did not find a master journal filled with bloody writing, nor did Holmes.

He did, however, find something nearly as obscene.

Holmes finally gave a grunt of satisfaction, and the safe door came open. I went to look over his shoulder.

There was money, quite a bit of money, in the currencies of several countries. Two passports, one well-used British document under the name of Harris, the other for a resident of Shanghai named Hawthorn. A velvet pouch containing a palmful of diamonds, cut and polished and splashing a startling brilliance across the dim-lit room. A bottle holding several ounces of unidentified liquid, with three small glass phials waiting to be filled. And seven envelopes of heavy white paper, folded shut but not sealed.

On each was written a number; in each was a sample of hair. As Holmes had anticipated, several were from animals-envelopes one and two had tufts of sheep's wool, while number four had three tail-feathers from a rooster. Number three, however, was definitely human, grey and about eight inches long. Number five was from a man, brown with a few grey hairs, its pomade staining the envelope. Number six held half a dozen strands of a horse's tail. And number seven: heavy black hair four inches long, one end neatly bound with white silk thread, attaching it to a beautifully worked gold wedding ring, a delicate version of the one I had seen on Damian's hand.