‘Shall I tell you what I think may have happened last night? I think that when you made your first remark as you stood in the french window at Hammer you said something that was near the truth. I think that either then, or perhaps earlier in the evening you had sallied out in search of your great trout. I think you regretted having flung it down on the bridge during your quarrel with Colonel Cartarette. You knew he wouldn’t touch it because he had told you so and had gone off, leaving it there. Did you not go down into the valley of the Chyne to retrieve the trout, and did you not find it gone from the bridge when you got there?’

The colour mounted in Mr Phinn’s face in uneven patches. He lowered his chin and looked quickly at Alleyn from under his meagre brows. But he said nothing.

‘If this is so,’ Alleyn went on, ‘and I am encouraged by your silence to hope that it may be, I can’t help wondering what you did next. Did you come straight back to Hammer and, seeing the lighted windows, make up your mind to accuse the Colonel of having pinched your fish after all? But no. If that had been so, your behaviour would have been different. You would not, before you were aware of his death, have trembled and gone white to the lips. Nor would you have invented your cock-and-bull story of wanting to tell the Colonel all about your catch: a story that was at once disproved when Lady Lacklander told us about your row with the Colonel over that very catch and by the fact that for a long time you have not been on visiting terms with your neighbour.’

Mr Phinn had turned aside, and Alleyn walked round him until they were again face to face.

‘How,’ he said, ‘is one to explain your behaviour of last night? Shall I tell you what I think? I think that when you arrived at Hammer Farm at five past one this morning, you knew already that Colonel Cartarette was dead.’

Still Mr Phinn said nothing.