“Let us take what used to be called a ‘lunar’ at the case. In a little while I must start interviewing people, but I’d like you fellows to get as clear an idea as possible of the case as we know it. At the moment we haven’t got so much as a smell of motive. Very well. Eight students, the model, and Miss Troy have used this studio every morning from Saturday the 10th until last Friday, the 16th. On Friday they used it until twelve-thirty, came away in dribbles, lunched at the house, and then, at different intervals, all went away with the exception of Wolf Garcia, a bloke who models and sculps. He stayed behind, saying that he would be gone when they returned on Sunday. The studio was not locked at any time, unless by Garcia, who slept in it. They reopened this morning with this tragedy. Garcia and his belongings had gone. That’s all. Any prints, Bailey?”

“There’s a good many blue smears round the edge, sir, but it’s unplaned wood underneath, and we can’t do much with it. It looks a bit as if someone had mopped it up with a painty rag.”

“There’s a chunk of paint-rag on the floor there. Is it dusty?”

“Yes, thick with it.”

“Possibly it was used for mopping up. Have a go at it.”

Alleyn began to prowl round the back of the throne.

“Hullo! More grist for the mill.” He pointed to a strip of wood lying in a corner of the studio. “Covered with indentations. It’s the ledge off an easel. That’s what was used for hammering. Take it next, Bailey. Let’s find an easel without a ledge. Detecting is so simple when you only know how. Mr. Hatchett has no ledge on his easel — therefore Mr. Hatchett is a murderer. Q.E.D. This man is clever. Oh, lawks-a-mussy-me, I suppose I’d better start off on the statements. How goes it, Bailey?”

“This paint-rag’s a mucky bit of stuff,” grumbled Bailey. “It’s been used for dusting all right. You can see the smudges on the platform. Same colour. I thought I might get a print off some of the smears of paint on the rag. They’re still tacky in places. Yes, here’s something. I’ll take this rag back and have a go at it, sir.”

“Right. Now the ledge.”

Bailey used his insufflator on the strip of wood.

“No,” he said, after a minute or two. “It’s clean.”

“All right. We’ll leave the studio to these two now, Fox. Try to get us as full a record of footprints as you can, Bailey. Go over the whole show. I can’t tell you what to look out for. Just do your stuff. And, by the way, I want photographs of the area round the window and the tyre-prints outside. You’d better take a cast of them and look out for any other manifestations round about them. If you come across any keys, try them for prints. Lock the place up when you’ve done. Good sleuthing.”

Fox and Alleyn returned to the house.

“Well, Brer Fox,” said Alleyn on the way, “how goes it with everybody?”

“The Yard’s still in the same old place, sir. Pretty busy lately.”

“What a life! Fox, I think I’ll see Miss Valmai Seacliff first.

“On the face of it she’s a principal witness.”

“What about Miss Troy, sir?” asked Fox.

Alleyn’s voice came quietly out of the darkness:

“I’ve seen her. Just before you came.”

‘What sort of a lady is she?”

“I like her,” said Alleyn. “Mind the step. Here’s the side door. I suppose we can use it. Hullo! Look here, Fox.”

He paused, his hand on Fox’s arm. They were close by a window. The curtains had been carelessly drawn and a wide band of light streamed through the gap. Alleyn stood a little to one side of this light and looked into the room. Fox joined him. They saw a long refectory table at which eight people sat. In the background, half in shadow, loomed the figure of a uniformed constable. Seven of the people round the table appeared to listen to the eighth, who was Agatha Troy. The lamplight was full on her face. Her lips moved rapidly and incisively; she looked from one attentive face to the other. No sound of her voice came to Alleyn and Fox, but it was easy to see that she spoke with urgency. She stopped abruptly and looked round the table as if she expected a reply. The focus of attention shifted. Seven faces were turned towards a thin, languid-looking young man with a blond beard. He seemed to utter a single sentence, and at once a stocky woman with black straight hair cut in a bang, sprang to her feet to answer him angrily. Troy spoke again. Then nobody moved. They all sat staring at the table.

“Come on,” whispered Alleyn.

He opened the side door and went along the passage to a door on the left. He tapped on this door. The policeman answered it.

“All right,” said Alleyn quietly, and walked straight in, followed by Fox and the constable. The eight faces round the table turned like automatons.

“Please forgive me for barging in like this,” said Alleyn to Troy.

“It’s all right,” said Troy. “This is the class. We were talking — about Sonia.” She looked round the table. “This is Mr. Roderick Alleyn,” she said.

“Good evening,” said Alleyn generally. “Please don’t move. If you don’t mind, I think Inspector Fox and I will join you for a moment. I shall have to ask you all the usual sort of things, you know, and we may as well get it over. May we bring up a couple of chairs?”

Basil Pilgrim jumped up and brought a chair to the head of the table.

“Don’t worry about me, sir,” said Fox. “I’ll just sit over here, thank you.”

He settled himself in a chair by the sideboard. Alleyn sat at the head of the table, and placed his notebook before him.

“The usual thing,” he said, looking pleasantly round the table, “is to interview people severally. I think I shall depart from routine for once and see if we can’t work together. I have got your names here, but I don’t know which of you is which. I’ll just read them through, and if you don’t mind— ”

He glanced at his notes.

“Reminiscent of a roll-call, I’m afraid, but here goes. Miss Bostock?”

“Here,” said Katti Bostock.

“Thank you. Mr. Hatchett?”

“That’s me.”

“Miss Phillida Lee?”

Miss Lee made a plaintive murmuring sound. Malmsley said: “Yes.” Pilgrim said: “Here.” Valmai Seacliff merely turned her head and smiled.

“That’s that,” said Alleyn. “Now then. Before we begin I must tell you that in my opinion there is very little doubt that Miss Sonia Gluck has been deliberately done to death. Murdered.”

They seemed to go very still.

“Now, as you all must realise, she was killed by precisely the means which you discussed and worked out among yourselves ten days ago. The first question I have to put to you is this. Has any one of you discussed the experiment with the dagger outside this class? I want you to think very carefully. You have been scattered during the week-end, and it is possible, indeed very likely, that you may have talked about the pose, the model, and the experiment with the knife. This is extremely important, and I ask you to give me a deliberated answer.”

He waited for quite a minute.

“I take it that none of you have spoken of this matter, then,” said Alleyn.

Cedric Malmsley, leaning back in his chair, said: “Just a moment.”

“Yes, Mr. Malmsley?”

“I don’t know, I’m sure, if it’s of any interest,” drawled Malmsley, “but Garcia and I talked about it on Friday afternoon.”

“After the others had gone up to London?”

“Oh, yes. I went down to the studio, you see, after lunch. I did some work there. Garcia was messing about with his stuff. He’s usually rather sour when he’s working, but on Friday he babbled away like the brook.”

“What about?”

“Oh,” said Malmsley vaguely, “women and things. He’s drearily keen on women, you know. Tediously over-sexed.” He turned to the others. “Did you know he and Sonia were living together in London?”

“I always said they were,” said Valmai Seacliff.

“Well, my sweet, it seems you were right.”