'That’s all very well,' replied the detective; 'but why did he hide? Why did he climb up that crooked little stairway and stop there; it led nowhere.'
'Why, because it led nowhere, of course,' cried Father Brown explosively. 'Anybody who clapped eyes on that blind alley ending in mid-air might have known an artist would want to go there, just as a child would.'
He stood blinking for a moment, and then said apologetically: 'I beg your pardon; but it seems odd that none of them understand these things. And then there was another thing. Don’t you know that everything has, for an artist, one aspect or angle that is exactly right? A tree, a cow, and a cloud, in a certain relation only, mean something; as three letters, in one order only, mean a word. Well, the view of that illuminated garden from that unfinished bridge was the right view of it. It was as unique as the fourth dimension. It was a sort of fairy foreshortening; it was like looking down at heaven and seeing all the stars growing on trees and that luminous pond like a moon fallen flat on the fields in some happy nursery tale. He could have looked at it for ever. If you told him the path led nowhere, he would tell you it had led him to the country at the end of the world. But do you expect him to tell you that in the witness-box? What would you say to him if he did? You talk about a man having a jury of his peers. Why don’t you have a jury of poets?'
'You talk as if you were a poet yourself,' said Bagshaw.
'Thank your stars I’m not,' said Father Brown. 'Thank your lucky stars a priest has to be more charitable than a poet. Lord have mercy on us, if you knew what a crushing, what a cruel contempt he feels for the lot of you, you’d feel as if you were under Niagara.'
'You may know more about the artistic temperament than I do,' said Bagshaw after a pause; 'but, after all, the answer is simple. You can only show that he might have done what he did, without committing the crime. But it’s equally true that he might have committed the crime. And who else could have committed it?'
'Have you thought about the servant, Green?' asked Father Brown, reflectively. 'He told a rather queer story.'
'Ah,' cried Bagshaw quickly, 'you think Green did it, after all.'
'I’m quite sure he didn’t,' replied the other. 'I only asked if you’d thought about his queer story. He only went out for some trifle, a drink or an assignation or what not. But he went out by the garden door and came back over the garden wall. In other words, he left the door open, but he came back to find it shut. Why? Because Somebody else had already passed out that way.'
'The murderer,' muttered the detective doubtfully. 'Do you know who he was?'
'I know what he looked like,' answered Father Brown quietly. 'That’s the only thing I do know. I can almost see him as he came in at the front door, in the gleam of the hall lamp; his figure, his clothes, even his face!'
'What’s all this?'
'He looked like Sir Humphrey Gwynne,' said the priest.
'What the devil do you mean?' demanded Bagshaw. 'Gwynne was lying dead with his head in the pond.'
'Oh, yes,' said Father Brown.
After a moment he went on: 'Let’s go back to that theory of yours, which was a very good one, though I don’t quite agree with it. You suppose the murderer came in at the front door, met the Judge in the front hall, struggling with him and breaking the mirror; that the judge then retreated into the garden, where he was finally shot. Somehow, it doesn’t sound natural to me. Granted he retreated down the hall, there are two exits at the end, one into the garden and one into the house. Surely, he would be more likely to retreat into the house? His gun was there; his telephone was there; his servant, so far as he knew, was there. Even the nearest neighbours were in that direction. Why should he stop to open the garden door and go out alone on the deserted side of the house?'
'But we know he did go out of the house,' replied his companion, puzzled. 'We know he went out of the house, because he was found in the garden.'
'He never went out of the house, because he never was in the house,' said Father Brown. 'Not that evening, I mean. He was sitting in that bungalow. I read that lesson in the dark, at the beginning, in red and golden stars across the garden. They were worked from the hut; they wouldn’t have been burning at all if he hadn’t been in the hut. He was trying to run across to the house and the telephone, when the murderer shot him beside the pond.'
'But what about the pot and the palm and the broken mirror?' cried Bagshaw. 'Why, it was you who found them! It was you yourself who said there must have been a struggle in the hall.'
The priest blinked rather painfully. 'Did I?' he muttered. 'Surely, I didn’t say that. I never thought that. What I think I said, was that something had happened in the hall. And something did happen; but it wasn’t a struggle.'
'Then what broke the mirror?' asked Bagshaw shortly.
'A bullet broke the mirror,' answered Father Brown gravely; 'a bullet fired by the criminal. The big fragments of falling glass were quite enough to knock over the pot and the palm.'
'Well, what else could he have been firing at except Gwynne?' asked the detective.
'It’s rather a fine metaphysical point,' answered his clerical companion almost dreamily. 'In one sense, of course, he was firing at Gwynne. But Gwynne wasn’t there to be fired at. The criminal was alone in the hall.'
He was silent for a moment, and then went on quietly. 'Imagine the looking-glass at the end of the passage, before it was broken, and the tall palm arching over it. In the half-light, reflecting these monochrome walls, it would look like the end of the passage. A man reflected in it would look like a man coming from inside the house. It would look like the master of the house – if only the reflection were a little like him.'
'Stop a minute,' cried Bagshaw. 'I believe I begin – '
'You begin to see,' said Father Brown. 'You begin to see why all the suspects in this case must be innocent. Not one of them could possibly have mistaken his own reflection for old Gwynne. Orm would have known at once that his bush of yellow hair was not a bald head. Flood would have seen his own red head, and Green his own red waistcoat. Besides, they’re all short and shabby; none of them could have thought his own image was a tall, thin, old gentleman in evening-dress. We want another, equally tall and thin, to match him. That’s what I meant by saying that I knew what the murderer looked like.'
'And what do you argue from that?' asked Bagshaw, looking at him steadily.
The priest uttered a sort of sharp, crisp laugh, oddly different from his ordinary mild manner of speech.
'I am going to argue,' he said, 'the very thing that you said was so ludicrous and impossible.'
'What do you mean?'
'I’m going to base the defence,' said Father Brown, 'on the fact that the prosecuting counsel has a bald head.'
'Oh, my God!' said the detective quietly, and got to his feet, staring.
Father Brown had resumed his monologue in an unruffled manner.
'You’ve been following the movements of a good many people in this business; you policemen were prodigiously interested in the movements of the poet, and the servant, and the Irishman. The man whose movements seem to have been rather forgotten is the dead man himself. His servant was quite honestly astonished at finding his master had returned. His master had gone to a great dinner of all the leaders of the legal profession, but had left it abruptly and come home. He was not ill, for he summoned no assistance; he had almost certainly quarrelled with some leader of the legal profession. It’s among the leaders of that profession that we should have looked first for his enemy. He returned, and shut himself up in the bungalow, where he kept all his private documents about treasonable practices. But the leader of the legal profession, who knew there was something against him in those documents, was thoughtful enough to follow his accuser home; he also being in evening-dress, but with a pistol in his pocket. That is all; and nobody could ever have guessed it except for the mirror.'