'Yes.'

'Before or afterwards?'

'What do you mean?'

'Did the clothing arrive before the skin, or the skin before the clothing?'

'Oh, I see. No, they arrived together.'

'At the same time?'

'Yes.'

'By the same police officer?'

'Yes.'

'In the same parcel?'

'Yes.'

'Who was the police officer?'

'I have no idea. I see so many. Besides, they all look young to me nowadays, so they all look the same.'

'Do you remember what he said?'

'Sir Arthur, this was over three years ago. There is not the slightest reason why I should remember a word he said. He would merely have told me that the parcel came from Inspector Campbell. He might have said what was in it. He might have said the items were for examination, but I hardly needed to be told that, did I?'

'And during the time these items were in your possession, they were kept scrupulously apart, the skin and the clothing? I do not intend to sound like counsel.'

'You do a very good likeness, if I may say so. And naturally I see where you are heading. There was no possibility of contamination in my laboratory, I can assure you.'

'I was not for a moment suggesting it, Dr Butter. I was heading in a different direction. Can you describe to me the parcel you received?'

'Sir Arthur, I can see exactly where you are heading. I have not stood cross-examination by defence counsel for these last twenty years without recognizing such an approach, or without having to answer for the procedures of the police. You were hoping I might say that the skin and the clothing were all rolled up together in some old piece of sacking into which the police had incompetently stuffed them. In which case you impugn my integrity as well as theirs.'

There was a steeliness now overlaying Dr Butter's civility. This was a witness you would always prefer to have on your side.

'I would not do such a thing,' said Arthur mollifyingly.

'You just have, Sir Arthur. You implied that I might have ignored the possibility of contamination. The items were separately wrapped and sealed, and no amount of shaking them around could have made the hairs escape from one package into the other.'

'I am obliged to you, Dr Butter, for eliminating this possibility.' And thus leaving it down to a choice of two: police incompetence before the items were packed separately, or police malice while this was happening. Well, he had pressed Butter far enough. Except… 'May I ask one more question? It is purely factual.'

'Of course. Forgive my irritation.'

'It is understandable. I was behaving too much like a defence counsel, as you observed.'

'It was not so much that. It is this. I have worked with the Staffordshire Constabulary for twenty years and more. Twenty years of going to court and having to answer sly questions based on assumptions I know to be false. Twenty years of seeing a jury's ignorance being played to. Twenty years of presenting evidence which is as clear and unambiguous as I can make it, which is based on rigorous scientific analysis, and then being treated, if not as a fraud, then as someone who is merely giving an opinion, that opinion being no more valuable than the next man's. Except that the next man does not have a microscope and if he did would not be competent to focus it. I state what I have observed – what I know – and find myself being told disdainfully that this is merely what I happen to think.'

'I entirely sympathize,' said Sir Arthur.

'I wonder. In any case, your question.'

'At what time of day did you receive the police parcel?'

'What time? About nine o'clock.'

Arthur was amazed by such despatch. The pony had been discovered at about 6.20, Campbell was still in the field at the time George was leaving home to catch the 7.39, he arrived at the Vicarage with Parsons and his band of specials some time before eight. Then they had to search the place, argue with the Edaljis…

'I'm sorry, Dr Butter, without sounding like counsel again, surely it was later than that?'

'Later? Certainly not. I know what time the parcel arrived. I remember complaining. They insisted on putting the parcel into my hands that day. I told them I could not possibly stay till after nine. I had my watch out when it arrived. Nine o'clock.'

'The mistake is entirely mine. I thought you meant nine o'clock in the morning.'

Now it is the surgeon's turn to look surprised. 'Sir Arthur, the police are, in my experience, both competent and industrious. Also honest. But they are not miracle-workers.'

Sir Arthur agreed, and the two men parted on friendly terms. But afterwards he found himself thinking exactly that: the police are miracle-workers. They are able to make twenty-nine horse hairs pass from one sealed package to another merely by the power of thought. Perhaps he should write them up for the Society of Psychical Research.

Yes, he might compare them to apport mediums, who were supposedly able to dematerialize objects and then rematerialize them, making showers of ancient coins fall upon the séance table, not to mention small Assyrian tablets and semi-precious stones. This was one branch of spiritism about which Arthur remained deeply sceptical; indeed, the most amateur detective was usually able to trace the ancient coins to the nearest numismatist's. As for the fellows who dealt in snakes and tortoises and live birds: Arthur thought they belonged more in the circus or the conjuror's booth. Or the Staffordshire Constabulary.

He was getting skittish. But that was just exhilaration. Twelve hours – therein lay his answer. The police had the evidence in their possession for twelve hours before delivering it to Dr Butter. Where had it been, who had charge of it, how had it been handled? Was there casual contamination, or a particular act done with the specific intention of incriminating George Edalji? Almost certainly, they would never find out, not without a deathbed confession – and Arthur had always been dubious of deathbed confessions.

His exhilaration mounted further when Dr Lindsay Johnson's report arrived at Undershaw. It was backed by two notebooks full of Johnson's detailed graphological analysis. The top man in Europe judged that none of the letters submitted to him, whether penned by malevolent schemer, religious maniac or degenerate boy, had any significant consonance with genuine documents written by George Edalji. In certain examples there was a kind of specious resemblance; but this was no more than you would expect from a forger who admitted trying to counterfeit another's handwriting. You would expect him capable of achieving occasionally a plausible facsimile; yet there were always giveaway signs to prove that George had – literally – no hand in it.

The first part of Arthur's list was now more than half ticked off: Yelverton – Hairs – Letters – Eyesight. Then there was Green - still work to do on him – and Anson. He would beard the Chief Constable directly. 'I shall be much interested to note what Sherlock Holmes has to say about a case in real life…' had been Anson's sarcastic response. Well, then, Arthur would take him at his word; he would write up his findings so far, send them off to Anson, and invite his comments.

As he sat down at his desk to begin his draft, he felt, for the first time since Touie's death, a sense of the properness of things. After the depression and guilt and lethargy, after the challenge and the call to action, he was where he belonged: a man at a desk with a pen in his hand, eager to tell a story and to make people see things differently; while out there, up in London, waiting for him – although not for too much longer – was the woman who, from now on, would be his first reader and the first witness of his life. He felt charged with energy; the material teemed in his head; and his purpose was clear. He began with a sentence he had been working on in trains and hotels and taxicabs, something both dramatic and declaratory: