As I approached the gatekeeper looked up, red-faced with effort. His companion, a stocky young man with a face disfigured by warty growths, smiled nervously and bowed. Both had been working hard, and gave off a vile stink.

'Good morning, sir,' Bugge said. His tone was unctuous; doubtless he had been ordered to treat me with respect.

'Cruel weather.'

'Indeed it is, sir. Winter is come early again.'

'Now we are met, I would like to ask about your night-time routine.'

He nodded, leaning on his shovel. 'The whole precinct is patrolled twice every night, at nine and three-thirty. Either me or David here makes a complete round, checking every door.'

'And the gates? Are they locked at night?'

'Every night at nine. And opened at nine in the morning, after Prime. Not a dog could get in here when the gates are shut.'

'Not a cat,' the boy added. His eyes were sharp; he might be ugly but he was no fool.

'Cats can climb,' I suggested. 'And so can people.'

A touch of truculence appeared in the gatekeeper's face. 'Not a twelve-foot wall, they can't. You've seen it, sir, it's sheer; no one could scale it.'

'The wall is secure all round the monastery?'

'Except at the back. It's crumbled in places there, but it gives straight onto the marsh. No one would go wading through that, especially at night. People have taken a wrong step and disappeared over their heads in the mud-' he lifted a hand and pushed it down – 'glug.'

'If no one can get in, why do you patrol?'

He leaned close. I recoiled from his stench, but he seemed not to mind. 'People are sinful, sir, even here.' His manner became confidential. 'Things were very lax in the days of the old prior. When Prior Mortimus came, he ordered the night patrols, anyone out of bed reported straight to him. And that's what I do. Without fear or favour.' He smiled happily.

'What about the night of Commissioner Singleton's murder? Did you see anything that might indicate someone might have broken in?'

He shook his head. 'No, sir, I'll swear all was as it should have been between three-thirty and four-thirty, I made that round myself. I tried the courtyard door to the kitchen as usual and it was locked. I saw the commissioner, though.' He nodded self-importantly.

'Yes, I heard you did. Where?'

'On my round. I was passing through the cloister when I saw something moving and called out. It was the commissioner, fully dressed.'

'What was he about at that hour?'

'He said he had a meeting, sir.' He smiled, enjoying the attention. 'He said if I met any of the brethren and they said they were on their way to see him, I was to let them pass.'

'So he was on his way to meet someone!'

'I would say so. He was near enough the kitchens, as well.'

'What time was this?'

'I'd say about a quarter past four. I was near the end of my round then.'

I nodded at the great bulk behind us. 'Is the church locked at night?'

'No sir, never. But I went round it as usual before checking the cloister, and all was normal. Then I was back in my house at half-past four. Prior Mortimus has given me a little clock,' he said proudly, 'and I always check the time. I slept a little, leaving David on watch, then I was woken by the great hue and cry at five.'

'So Commissioner Singleton was on his way to meet one of the monks. It does seem then that the great crime committed here a week ago was the work of a monk.'

He hesitated. 'I say no one broke in, that's all I know. It's impossible.'

'Not impossible, but unlikely, I agree.' I nodded. 'Thank you, Master Bugge, you have been most helpful.' I set my staff before me and turned away, leaving them once more to their labours.

I retraced my steps to where a green door marked the counting house. Entering without knocking, I found myself in a room that reminded me of my own world: whitewashed walls lined with shelves of ledgers, any bare patches covered with lists and bills. Two monks sat working at desks. One, counting out coins, was elderly and rheumy-eyed. The other, frowning over a ledger, was the young bearded monk who had lost at cards the night before. Behind them stood a chest with the largest lock I had ever seen; the abbey's funds, no doubt.

The two monks jumped to their feet at my entry. 'Good morning,' I said. My breath made a mist in the air, for the room was unheated. 'I seek Brother Edwig.'

The young monk glanced at an inner door. 'Brother Edwig is with the abbot-'

'In there? I'll join them.' I passed to the inner door, ignoring a hand half-raised in protest. Opening it, I found myself facing a staircase. It led to a little landing, where a window gave a view out over the white landscape. Opposite, voices could be heard behind a door. I paused outside, but could not make out what it was they were saying. I opened the door and went in.

Abbot Fabian was speaking to Brother Edwig in peevish tones. 'We should ask more. It doesn't befit our status to let it go for less than three hundred

'I need the money in my coffers now, Lord Abbot. If he'll p-pay cash for the land, we should t-take it!' Despite his stutter, there was a steely note in the bursar's voice. Abbot Fabian looked round, disconcerted.

'Oh, Master Shardlake-'

'Sir, this is a private conversation,' the bursar said, his face filled with sudden anger.

'I am afraid there is no such thing where I am concerned. If I knocked and waited at every door, who knows what I might miss?'

Brother Edwig controlled himself, fluttering his hands, once more the fussy bureaucrat. 'N-no, of course, forgive me. We w-were discussing the monastery finances, some lands we must sell to meet the costs of the building w-works, a mat-mat-' His face reddened again as he struggled for words.

'A matter of no concern to your investigation,' the abbot finished with a smile.

'Brother bursar, there is a relevant issue I would discuss.' I took a seat at an oak desk with many drawers, the only furniture in the little room apart from yet more shelves of ledgers.

'I am at your service, sir, of course.'

'Dr Goodhaps tells me that on the day he died Commissioner Singleton was working on an account book he had obtained from your office. And that afterwards it disappeared.'

'It did not d-disappear, sir. It was returned to the counting house.'

'Perhaps you could tell me what it was.'

He thought a moment. 'I cannot remember. The inf-firmary accounts, I believe. We keep accounts for all the different departments – sacristy, infirmary and so on, and a central set for the whole monastery.'

'Presumably if Commissioner Singleton took account books from you, you would keep a record.

'I m-most certainly would.' He frowned petulantly. 'But more than once he took books without telling me or my assistant, and we had to spend the day hunting for something he had taken.'

'So there is no actual record of all he took?'

The bursar spread his arms. 'How c-could there be, w-when he helped himself? I am s-sorry-'

I nodded. 'All is in order now, in the counting house.

'Thank the Lord.'

I stood up. 'Very well. Please have all the account books for the last twelve months brought to my room in the infirmary. Oh, and those from the departments as well.'

'All the books?' The bursar could not have looked more aghast had I ordered him to remove his habit and parade naked in the snow. 'That would be very disruptive, it would bring the work of the counting house to a halt-'

'It will only be for one night. Maybe two.'

He seemed set to argue further, but Abbot Fabian interjected.

'We must co-operate, Edwig. The books will be brought to you as soon as they can be fetched, Commissioner.'