seems pretty clear now what he did. He was always a great swimmer and used to come down in his dressing-gown every morning for a dip in the river. Well, he came down as usual, and left his dressing-gown on the bank; it's lying there still. But he also left a message saying he was going for his last swim and then death, or something like that.'
'Where did he leave the message?' asked Father Brown.
'He scrawled it on that tree there, overhanging the water, I suppose the last thing he took hold of; just below where the dressing-gown's lying. Come and see for yourself.'
Father Brown ran down the last short slope to the shore and peered under the hanging tree, whose plumes were almost dipping in the stream. Sure enough, he saw on the smooth bark the words scratched conspicuously and unmistakably: 'One more swim and then drowning. Good-bye. Hubert Sand.' Father Brown's gaze travelled slowly up the bank till it rested on a gorgeous rag of raiment, all red and yellow with gilded tassels. It was the dressing-gown and the priest picked it up and began to turn it over. Almost as he did so he was conscious that a figure had flashed across his field of vision; a tall dark figure that slipped from one clump of trees to another, as if following the trail of the vanishing lady. He had little doubt that it was the companion from whom she had lately parted. He had still less doubt that it was the dead man's secretary, Mr Rupert Rae.
'Of course, it might be a final afterthought to leave the message,' said Father Brown, without looking up, his eye riveted on the red and gold garment. 'We've all heard of love-messages written on trees; and I suppose there might be death-messages written on trees too.'
'Well, he wouldn't have anything in the pockets of his dressing-gown, I suppose,' said young Sand. 'And a man might naturally scratch his message on a tree if he had no pens, ink or paper.'
'Sounds like French exercises,' said the priest dismally. 'But I wasn't thinking of that.' Then, after a silence, he said in a rather altered voice:
'To tell the truth, I was thinking whether a man might not naturally scratch his message on a tree, even if he had stacks of pens, and quarts of ink, and reams of paper.'
Henry was looking at him with a rather startled air, his eyeglasses crooked on his pug-nose. 'And what do you mean by that?' he asked sharply.
'Well,' said Father Brown slowly, 'I don't exactly mean that postmen will carry letters in the form of logs, or that you will ever drop a line to a friend by putting a postage stamp on a pinetree. It would have to be a particular sort of position — in fact, it would have to be a particular sort of person, who really preferred this sort of arboreal correspondence. But, given the position and the person, I repeat what I said. He would still write on a tree, as the song says, if all the world were paper and all the sea were ink; if that river flowed with everlasting ink or all these woods were a forest of quills and fountain-pens.'
It was evident that Sand felt something creepy about the priest's fanciful imagery; whether because he found it incomprehensible or because he was beginning to comprehend.
'You see,' said Father Brown, turning the dressing-gown over slowly as he spoke, 'a man isn't expected to write his very best handwriting when he chips it on a tree. And if the man were not the man, if I make myself clear — Hullo!'
He was looking down at the red dressing-gown, and it seemed for the moment as if some of the red had come off on his finger; but both the faces turned towards it were already a shade paler.
'Blood!' said Father Brown; and for the instant there was a deadly stillness save for the melodious noises of the river.
Henry Sand cleared his throat and nose with noises that were by no means melodious. Then he said rather hoarsely: 'Whose blood?'
'Oh, mine,' said Father Brown; but he did not smile.
A moment after he said: 'There was a pin in this thing and I pricked myself. But I don't think you quite appreciate the point . . . the point of the pin. I do'; and he sucked his finger like a child.
'You see,' he said after another silence, 'the gown was folded up and pinned together; nobody could have unfolded it — at least without scratching himself. In plain words, Hubert Sand never wore this dressing-gown. Any more than Hubert Sand ever wrote on that tree. Or drowned himself in that river.'
The pince-nez tilted on Henry's inquiring nose fell off with a click; but he was otherwise motionless, as if rigid with surprise.
'Which brings us back,' went on Father Brown cheerfully, 'to somebody's taste for writing his private correspondence on trees, like Hiawatha and his picture-writing. Sand had all the time there was, before drowning himself. Why didn't he leave a note for his wife like a sane man? Or, shall we say… Why didn't the Other Man leave a note for the wife like a sane man? Because he would have had to forge the husband's handwriting; always a tricky thing now that experts are so nosey about it. But nobody can be expected to imitate even his own handwriting, let alone somebody else's when he carves capital letters in the bark of a tree. This is not a suicide, Mr Sand. If it's anything at all, it's a murder.'
The bracken and bushes of the undergrowth snapped and crackled as the big young man rose out of them like a leviathan, and stood lowering, with his thick neck thrust forward.
'I'm no good at hiding things,' he said, 'and I half-suspected something like this — expected it, you might say, for a long time. To tell the truth, I could hardly be civil to the fellow — to either of them, for that matter.'
'What exactly do you mean?' asked the priest, looking him gravely full in the face.
'I mean,' said Henry Sand, 'that you have shown me the murder and I think I could show you the murderers.'
Father Brown was silent and the other went on rather jerkily.
'You said people sometimes wrote love-messages on trees. Well, as a fact, there are some of them on that tree; there are two sort of monograms twisted together up there under the leaves — I suppose you know that Lady Sand was the heiress of this place long before she married; and she knew that damned dandy of a secretary even in those days. I guess they used to meet here and write their vows upon the trysting-tree. They seem to have used the trysting-tree for another purpose later on. Sentiment, no doubt, or economy.'
'They must be very horrible people,' said Father Brown.
'Haven't there been any horrible people in history or the police-news?' demanded Sand with some excitement. 'Haven't there been lovers who made love seem more horrible than hate? Don't you know about Bothwell and all the bloody legends of such lovers?'
'I know the legend of Bothwell,' answered the priest. 'I also know it to be quite legendary. But of course it's true that husbands have been sometimes put away like that. By the way, where was he put away? I mean, where did they hide the body?'
'I suppose they drowned him, or threw him in the water when he was dead,' snorted the young man impatiently.
Father Brown blinked thoughtfully and then said: 'A river is a good place to hide an imaginary body. It's a rotten bad place to hide a real one. I mean, it's easy to say you've thrown it in, because it might be washed away to sea. But if you really did throw it in, it's about a hundred to one it wouldn't; the chances of it going ashore somewhere are enormous. I think they must have had a better scheme for hiding the body than that — or the body would have been found by now. And if there were any marks of violence — '
'Oh, bother hiding the body,' said Henry, with some irritation; 'haven't we witness enough in the writing on their own devilish tree?'
'The body is the chief witness in every murder,' answered the other. 'The hiding of the body, nine times out of ten, is the practical problem to be solved.'
There was a silence; and Father Brown continued to turn over the red dressing-gown and spread it out on the shining grass of the sunny shore; he did not look up. But, for some time past he had been conscious that the whole landscape had been changed for him by the presence of a third party; standing as still as a statue in the garden.
'By the way,' he said, lowering his voice, 'how do you explain that little guy with the glass eye, who brought your poor uncle a letter yesterday? It seemed to me he was entirely altered by reading it; that's why I wasn't surprised at the suicide, when I thought it was a suicide. That chap was a rather low-down private detective, or I'm much mistaken.'
'Why,' said Henry in a hesitating manner, 'why, he might have been — husbands do sometimes put on detectives in domestic tragedies like this, don't they? I suppose he'd got the proofs of their intrigue; and so they —
