'I do.' He thought a moment. 'But – I cannot see him as a murderer. He seems a man of – strong affections, if you can call them that, but not one who would willingly do harm. Or be bold enough to strike.'

'Oh, he can be bold enough when he wants. And he has very strong affections. Violently strong. And where there are violent affections there may perhaps be violent hatreds too.'

He shook his head. 'I cannot see it. Please believe me, sir, I am not being awkward, but I cannot see Brother Gabriel as a killer.'

'I have felt sorry for the man, even liked him. But we can't decide these things on the basis of emotion. We need cold logic. How can we know whether someone is capable of murder or not after a few days' acquaintance? Especially in this place, where all our senses are heightened and distorted by danger?'

'I still can't see it, sir. He seems so – soft-natured.'

'We might as well accuse Brother Edwig on the basis that he is a despicable creature, more like an animated calculus than a man. He is full of deceits too, and lusts as well, apparently. But that doesn't allow us to say he is a murderer.'

'He was away when Singleton was killed.'

'And Gabriel wasn't. And I can see a chain of motive for Gabriel. No, we must put emotion aside.'

'As you would have me do with Alice.'

'This is not the time to discuss that. Now, will you come with me to confront Gabriel?'

'Of course. I do want this killer caught too, sir.'

'Good. Then buckle on your sword again. Leave that other sword here, but bring the habit. Wring it out in the bowl first. Let us put these matters to the test.'

My heart was pounding as we went back outside, but my head was clear. It was well past midday now, and the sun hung low in a hazy sky; one of those great red winter suns that you can look straight into, as though all the fire were leached out of it. And, in that cold, so it felt.

Brother Gabriel was in the church. He sat in the nave with the old monk I had seen copying in the library, examining a great pile of ancient volumes. They looked up at our approach, Gabriel's eyes flickering uneasily between Mark and me.

'More ancient books, Brother?' I asked.

'These are our service books, sir, with the musical notations. No one prints them, we have to copy them when they fade.'

I picked one up. The pages were parchment; Latin words were marked phonetically and interspersed with red musical notation, different psalms and prayers for each day of the calendar, the ink faded at the edges from long years of handling. I dropped it on a bench.

'I have some questions, Brother.' I turned to the old monk. 'Perhaps you could leave us?' He nodded and scuttled away.

'Is something amiss?' the sacrist asked. There was a tremor in his voice.

'You have not heard, then? About the body found in the fish pond?'

His eyes opened wide. 'I have been engaged, I have just come from fetching Brother Stephen from the library. A body?'

'We believe it to be a girl who disappeared two years ago. One Orphan Stonegarden.'

His mouth dropped open. He half-rose, then sat again.

'Her neck was broken. It appears she was killed and thrown in the pond. There was a sword there too; we think the one that killed Commissioner Singleton. And this.' I nodded to Mark, who passed me the habit. I waved the badge under the sacrist's nose. Your robe, Brother Gabriel.'

He sat there gaping.

'The badge is yours?'

'Yes, yes it is. That – it must be the robe that was stolen.'

'Stolen?'

'Two weeks ago I sent a habit to the launderer and it never came back. I enquired, but it was never found. The servants steal habits now and then; our winter robes are good wool. Please, sir, you cannot think-'

I leaned over him. 'Gabriel of Ashford, I put it to you that you killed Commissioner Singleton. He knew of your past, and discovered some recent felony you could have been tried and executed for. So you killed him.'

'No.' He shook his head. 'No!'

'You hid the sword and your bloodied robe in the pond, which you knew to be a safe hiding place as you had used it before to hide that girl's body. Why kill Singleton in such a dramatic way, Brother Gabriel? And why did you kill the girl? Was it jealousy because Brother Alexander befriended her? Your fellow sodomite? And Novice Whelplay too, your other friend. He knew what had become of her, didn't he? But he wouldn't betray you. Not until the end, when he started talking in his illness, so you poisoned him. Since then you have seemed racked with pain, as one in an agony of conscience. It all fits, Brother.'

He stood up and faced me, gripping the back of his chair while he took a couple of long breaths. Mark's hand strayed to his sword.

'You are the king's commissioner,' he said, his voice shaking, 'but you harangue like a cheap lawyer. I have killed nobody.' He began to shout. 'Nobody! A sinner I am, but I have broken none of the king's laws these two years! You may enquire of every soul here, and in the town too if you wish, and you will find nothing! Nothing!' His voice echoed round the church.

'Calm yourself, Brother,' I said in measured tones. 'And answer me civilly.'

'Brother Alexander was neither my friend nor my enemy; he was a foolish, lazy old man. As for poor Simon,' he gave a sigh that was almost a groan, 'yes, he befriended the girl in his first days as a novice, I think they both felt lost and threatened here. I told him he should not be mixing with servants; that it would do him no good. He said she had told him she was being pestered-'

'By whom?'

'He would not say, she had sworn him to silence. It could have been one of half a dozen monks. I said he should not become involved in such things; he should get the girl to tell Brother Guy. He had just been made infirmarian after Alexander died. Of shame,' he added bitterly.

'And then she disappeared.'

A spasm twisted his face. 'Like everyone else I thought she had run away.' He looked at me bleakly, then went on in a new voice, cold and calm. 'Well, Commissioner, I see you have created a theory that gives you a solution. So perhaps now someone will be paid to give false testimony and send me to the gallows. Such things are done these days. I know what happened to Sir Thomas More.'

'No, Brother Gabriel, there will be no false witnesses. I will uncover the evidence I need.' I stepped closer to him. 'Be warned. You are under the gravest suspicion.'

'I am innocent.'

I looked into his face a moment, then stepped back. 'I will not have you arrested now, but for the present you will not leave the monastery precincts. If you attempt to leave that will be taken as an admission of guilt. You understand?'

'I will not leave.'

'Be available to speak to me whenever I require. Come, Mark.'

I got up and strode away, leaving Brother Gabriel amidst his pile of books. Outside the church I struck the stone doorway with my hand.

'I thought I had him.'

'Do you still think him guilty?'

'I don't know. I thought if I confronted him and he was guilty he'd collapse. But,' I shook my head, 'he's hiding something, I know it. He called me a haranguing lawyer and perhaps I am, but if twenty years about the courts have taught me anything it's when a man is concealing things. Come.'

'Where now?'

'The laundry. We can check his story and see this Luke at the same time.'

The laundry was housed in a large outhouse next to the buttery. Steam issued from ventilator grilles, and I had seen servants going in and out of there with baskets of clothes. I unlatched the heavy wooden door and stepped inside. Mark closed it behind him.