Peter considered this.
"Imagination isn't Gerald's strong point," he admitted.
"I suppose they do hang peers? They can't be beheaded on Tower Hill or anything?"
"I'll look it up," said Parker; "but they certainly hanged Earl Ferrers in 1760."
"Did they, though?" said Lord Peter. "Ah, well, as the old pagan said of the Gospels, after all, it was a long time ago, and we'll hope it wasn't true."
"It's true enough," said Parker; "and he was dissected and anatomised afterwards. But that part of the treatment is obsolete."
"We'll tell Gerald about it," said Lord Peter, "and persuade him to take the matter seriously. Which are the boots he wore Wednesday night?"
"These," said Parker, "but the fool's cleaned them."
"Yes," said Lord Peter bitterly. "H'm! a good heavy lace-up boot-the sort that sends the blood to the head."
"He wore leggings, too," said Parker; "these." Rather elaborate preparations for a stroll in the garden. But, as you were just going to say, the night was wet. I must ask Helen if Gerald ever suffered from insomnia."
"I did. She said she thought not as a rule, but that he occasionally had toothache, which made him restless."
"It wouldn't send one out of doors on a cold night though. Well, let's get downstairs."
They passed through the billiard-room, where the Colonel was making a sensational break, and into the small conservatory which led from it.
Lord Peter looked gloomily round at the chrysanthemums and boxes of bulbs.
"These damned flowers look jolly healthy," he said.
"Do you mean you've been letting the gardener swarm in here every day to water 'em?"
"Yes," said Parker apologetically, "I did. But he's had strict orders only to walk on these mats."
"Good," said Lord Peter. "Take 'em up, then, and let's get to work."
With his lens to his eye he crawled cautiously over the floor.
"They all came through this way, I suppose," he said.
"Yes," said Parker. "I've identified most of the marks. People went in and out. Here's the Duke. He comes in from outside. He trips over the body." (Parker had opened the outer door and lifted some matting, to show a trampled patch of gravel, discoloured with blood.) "He kneels by the body. Here are his knees and toes. Afterwards he goes into the house, through the conservatory, leaving a good impression in black mud and gravel just inside the door." Lord Peter squatted carefully over the marks.
"It's lucky the gravel's so soft here," he said.
"Yes. It's just a patch. The gardener tells me it gets trampled and messy just here owing to his corning cans from the water-trough. They fill the trough from the well every so often, and then carry the water away in cans. It got extra bad this year, and they put down fresh gravel a few weeks ago."
"Pity they didn't extend their labours all down the path while they were about it," grunted Lord Peter, who was balancing himself precariously on a small piece of sacking. "Well, that bears out old Gerald so far. Here's an elephant been over this bit of box border. Who's that?"
"Oh, that's a constable. I put him at eighteen stone. He's nothing. And this rubber sole with a patch on it is Craikes. He's all over the place. This squelchy-looking thing is Mr. Arbuthnot in bedroom slippers, and the galoshes are Mr. Pettigrew-Robinson. We can dismiss all those. But now here, just coming over the threshold, is a woman's foot in a strong shoe. I make that out to be Lady Mary's. Here it is again, just at the edge of the well. She came out to examine the body."
"Quite so," said Peter; "and then she came in again, with a few grains of red gravel on her shoes. Well, that's all right. Hullo!"
On the outer side of the conservatory were some shelves for small plants, and, beneath these, a damp and dismal bed of earth, occupied, in a sprawling and lackadaisical fashion, by stringy cactus plants and a sporadic growth of maidenhair fern, and masked by a row of large chrysanthemums in pots.
"What've you got?" inquired Parker, seeing his friend peering into this green retreat.
Lord Peter withdrew his long nose from between two [garbled] and said: "Who put what down here?"
Parker hastened to the place. There, among the cacti, was certainly the clear mark of some oblong object with corners, that had been stood out of sight on the earth behind the pots.
"It's a good thing Gerald's gardener ain't one of those conscientious blighters that can't even let a cactus alone for the winter," said Lord Peter, "or he'd've tenderly lifted these little drooping heads-oh! damn and blast the beastly plant for a crimson porcupine! You measure it."
Parker measured it.
"Two and a half feet by six inches," he said. "And fairly heavy, for it's sunk in and broken the plants about. Was it a bar of anything?"
"I fancy not," said Lord Peter. "The impression is deeper on the farther side. I think it was something bulky set up on edge, and leaned against the glass. If you asked for my private opinion I should guess that it was a suitcase."
"A suit-case!" exclaimed Parker. "Why a suitcase?"
"Why indeed? I think we may assume that it didn't stay here very long. It would have been exceedingly visible in the daytime. But somebody might very well have shoved it in here if they were caught with it-say at three o'clock in the morning-and didn't want it to be seen."
"Then when did they take it away?"
"Almost immediately, I should say. Before daylight, anyhow, or even Inspector Craikes could hardly have failed to see it."
"It's not the doctor's bag, I suppose?"
"No-unless the doctor's a fool. Why put a bag conveniently in a damp and dirty place out of the way when every law of sense and convenience would urge him to pop it down handy by the body? No. Unless Craikes or the gardener has been leaving things about, this was thrust away there on Wednesday night by Gerald, by Cathcart-or, I suppose, by Mary. Nobody else could be supposed to have anything to hide."
"Yes," said Parker, "one person."
"Who's that?"
"The Person Unknown."
"Who's he?"
For answer Mr. Parker proudly stepped to a row of wooden frames, carefully covered with matting. Stripping this away, with the air of a bishop unveiling a memorial, he disclosed a V-shaped line of footprints.
"These," said Parker, "belong to nobody-to nobody I've ever seen or heard of, I mean."
"Hurray!" said Peter.
" Then downwards/From the steep hill's edge/They tracked the footmarks small (only they're largish)."
"No such luck," said Parker. "It's more a case of:
" They followed from the earthy bank
Those footsteps one by one,
Into the middle of the plank;
And farther there were none!"
"Great poet, Wordsworth," said Lord Peter; "how often I've had that feeling. Now let's see. These footmarks-a man's No. 10 with worn-down heels and a patch on the left inner side-advance from the hard bit of the path which shows no footmarks; they come to the body-here, where that pool of blood is. I say, that's rather odd, don't you think? No? Perhaps not. There are no footmarks under the body? Can't say, it's such a mess. Well, the Unknown gets so far-here's a footmark deeply pressed in. Was he just going to throw Cathcart into the well? He hears a sound; he starts; he turns; he runs on tiptoe-into the shrubbery, by Jove!"
"Yes," said Parker, "and the tracks come out on one of the grass paths in the wood, and there's an end of them."
"H'm! Well, we'll follow them later. Now where did they come from?"
Together the two friends followed the path away from the house. The gravel, except for the little patch before the conservatory, was old and