He leaned back against the wall. 'My final task was St Erconwald's in Southwark.' Athelstan stared across at Cranston. 'My father prior chose well. My parents accused me of the murder of my brother. Every day in Southwark someone dies. Men and women drenched with drink, quarrelling and violently fighting each other. In some alleyway or runnel a man hacked to death for stealing ale. A woman slashed from jaw to groin found floating in a ditch. And then you, Sir John! Just in case I should forget, or withdraw, or hide behind my church walls, you are here, ready to lead me along the streets, remind me that there is no escape from murder, from witnessing the greatest sin of all – a man slaying his brother!'

Cranston drained his cup of wine and said, 'Perhaps your father prior is wiser than you think.'

'What do you mean?'

'I am writing a treatise, have been for years, on the maintenance of the king's peace in London. The most terrible crime is murder. The belief that a man can kill someone, walk away, and say, "I am not responsible". I am no theologian, Athelstan, nor a scripture scholar, but the first crime committed after Eden was one of murder: Cain plotting to slay his brother Abel and afterwards claiming he knew nothing about it.' Cranston grinned. 'The first great mystery – I mean murder. But nothing like what happened to your brother.' He turned and spat. 'That wasn't murder. That was young dreams and hot blood, minds crammed with stupid stories about Troy and Knights of the Round Table. No, murder is different. And why do men commit murder, Athelstan? For profit? And what will stop men murdering? Hanging, torture?' He shrugged. 'Go down to Newgate, as we will do later. The prison is packed with murderers, the gibbets are heavy like apple trees in the autumn, the branches bend with their rotten fruit.'

Cranston moved closer, his face more serious than Athelstan had ever seen it. 'What will prevent murder, robbery, arson, is when the perpetrator knows, believes, accepts in his heart, that he will be caught and he will be punished. The more vigilant we are, the fewer murders, the fewer deaths. The fewer women slashed from jaw to groin, the fewer men with their throats cut, hanging in a garret or swinging from some beam under a bridge. Your prior knows, Athelstan, that with your guilt and deep sense of justice, you are well suited to such a task.'

He laughed abruptly and went back to this wine cup. 'If your order produced more men like you, Athelstan, and fewer preachers and theologians, London would be a safer place. That's the reason I have brought you to this quiet garden, not to some tavern where I would drink myself senseless. No, I want to plot and catch an evil murderer. A man who has slain Thomas Springall and blamed it on poor Brampton, afterwards making his death look like suicide. I believe the same villain executed Vechey and strung his corpse up like carrion under London Bridge.'

Athelstan drank greedily from the water cup, refusing to look at Cranston. He had talked about his brother's death, and for the first time ever someone had not laid the blame at his door. Athelstan knew it would make no immediate difference but a seed had been planted in his soul. The possibility that he had committed a sin but no murder. That he would atone for it and so the slate would be wiped clean. He put down the cup.

'You say Springall was murdered by someone else, not Brampton?' he asked abruptly.

'I do,' said Cranston. 'And so do you. And how can we prove that? The loose thread in this rotten tapestry is Vechey. Now, you may remember when we inspected his corpse, we noticed the water had soaked him up to his knees?'

'Yes,' Athelstan nodded.

'We also know that if Vechey committed suicide he must have done it in the early hours, just before dawn. Correct?'

Again Athelstan nodded.

'But that is impossible,' Cranston continued with a self- satisfied smirk. 'You see, after midnight the Thames runs fast and full. The water rises and it would almost cover the arch. There would be, at the very most, a foot between the surface of the water and the beam Vechey used to hang himself.' He held up his stubby fingers. 'First, are we to accept that a man waded through water up to his neck to tie a noose to hang himself? Or that he hanged himself virtually under water? Yet when Vechey's corpse was found, somehow or other it had dried out except beneath the knees.'

Athelstan grinned. 'Mirabile dictu, Sir John! Of course the river would be full. Vechey would have had to swim out to hang himself and that is a logical contradiction. So what do you think happened?'

'Vechey was drugged or knocked on the head, the corpse being strung up for others to find.'

'But why such contrivance?'

'I have been wondering about that,' Cranston replied. 'Remember, we know very little about the man. Vechey was promiscuous, he liked soft and perfumed flesh but, being a respectable citizen, he would hunt well away from his home in Cheapside. So I think he went down to the stews and bawdy houses along the river. Somehow or other he was trapped, knocked on the head or drugged, and his body taken down to London Bridge. The noose was tied around his neck and strung over the beam. The murderer was very clever, the river bank was deserted. The bridge, as the man- nikin told us, was a favourite place for people to commit suicide. The murderer made one mistake. He probably inspected the area when the water had fallen well below the starlings. He forgot that when he came to hang up Vechey's corpse the river would have risen, covering any suitable platform for a suicide to stand on.'

'Yet he still went ahead. Why?'

'Because Vechey was probably dead, strangled before he ever reached that bridge, and what else could the murderer do with the corpse? Throw it in the river still bearing the noose-mark, or cart it round London and risk capture looking for a new gibbet!'

Athelstan smiled. 'Perfect, Sir John.'

'And Brampton?'

'You may remember, or perhaps not,' Athelstan replied, that Brampton's corpse was dressed in hose and a linen shirt. First, do we really accept that a man in the act of undressing suddenly decides halfway through that he will hang himself and goes up to the garret without his boots on to carry out the terrible act? Now, even if he had, the garret floor was covered with pieces of glass and dirt. However, when I examined the soles of Brampton's feet, there were no marks or cuts. Yet there should have been if he had walked across that floor without his boots on. In fact, there was very little dust on the soles of his hose. The only conclusion is that Brampton died like Vechey. He was carried up to that garret, probably in a state of stupor, drunk or drugged. The rope was tied round his neck. He fought for a while, hence the strands of cord found under the finger nails, but he was murdered and left there to hang so others would think he had taken his own life.'

Cranston pursed his lips and smiled.

'Most logical, Brother.'

'The other factor,' Athelstan continued, 'is that Vechey and Brampton supposedly hanged themselves. Now, I examined the bruise on each of the corpses. It is a remarkable coincidence that two men, relative strangers, put a noose knot in exactly the same place, Vechey copying Brampton in every particular when he hanged himself. I went down to the execution yard where I saw three corpses. The executioner himself said that each hangman has his own hall-mark. The three corpses I studied there had the noose placed in the same spot. Vechey and Brampton also had the noose placed in the same spot. The only logical conclusion is that Brampton and Vechey were hanged by the same person.'

Athelstan picked up a quill with a modest flourish, uncapped the inkhorn and dipped in his pen. Cranston leant nearer. Athelstan found himself relishing the closeness. He felt as if he was back in time with his brother, plotting some mischief.