‘Here, you lay off Bert!’ shouted Simon. ‘He’s right out of this. He’s got his agreement.’

‘His motive,’ Mr Falls continued precisely, ‘appears at first to be revenge. Revenge for an attempt on his life.’

‘Revenge, my foot. They buried the hatchet.’

‘In order to resurrect a much more valuable one in the form of Rewi’s adze. Yes, yes, I agree that the revenge motive breaks down but it does well enough for a red herring. Dr Ackrington: your motive, at first, would seem to be a kind of quintessence of fury. You believed Questing to be a traitor and you could find little support in your efforts to bring him to book.’

‘It’s perfectly obvious to me now, Falls, that the man was done to death by someone from the native settlement. No doubt some wretched youth in the pay of the enemy.’

‘Ah! The Maori theme. Shall we leave that for the moment? Now, in your case, Colonel, the motive is much more credible. Forgive me for introducing a painful theme but your position was, I’m afraid, only too clear. Questing’s extraordinary assumption of proprietorship alone would have betrayed it. He was, as Mr Bell remarked a little while ago, a keen man of business. Have you not benefited greatly by his death…’

‘Cut that out!’ Simon cried out angrily. ‘You damn well lay off my father.’

‘Be quiet, Simon,’ said the Colonel.

‘…as indeed,’ Mr Falls completed his sentence, ‘have all the members of your family?’ He looked at his hands, lightly clasped on the table. ‘The Maori element,’ he said, and paused. ‘Revenge for the violation of a sacred object? Not an inconsiderable motive. To my mind, a perfectly credible motive. But did anybody beside Mr Gaunt, outside the Old Firm, as I feel tempted to call the Smith-Questing-Saul link-up, know of the disappearance of the adze? And beyond that there seems to be a jealousy theme centring round your mind, Colonel. Questing appears to have supplanted the man with the debatable shirt. Eru. Eru Saul.’

‘But my dear Falls,’ said Dr Ackrington, ‘you seem to accept Questing’s letter. Surely, then, the murderer is the spy?’

‘Certainly. It is most probable. The point I am leading up to is this. It seems to me that in this case motive should, for the moment, be disregarded. There are too many motives. Let us look instead at circumstances. At fact.’

‘Oh, for God’s sake,’ Gaunt said wearily.

‘Four apparent inexplicable points have interested me enormously. The railway signal. Eru Saul’s shirt. The pohutukawa trees. The misplaced flag. It seems to me that if an explanation is found that will apply equally to these four parts, then we shall have gone a long way towards solving the whole. These are factual things.’

‘How about yourself?’ Simon demanded abruptly. ‘If it comes to facts you look pretty fishy, don’t you?’