"That's easy. Offhand I'd say Despard. The man's got plenty of nerve, he's used to a dangerous life where you've got to act quickly. He wouldn't mind taking a risk. It doesn't seem to me likely the women are in on this. Take a bit of strength, I should imagine."

"Not so much as you might think. Take a look at this."

Rather like a conjuror, Battle suddenly produced a long, thin instrument of gleaming metal with a small, round jeweled head.

Doctor Roberts leaned forward, took it, and examined it with rich, professional appreciation. He tried the point and whistled. "What a tool! What a tool! Absolutely made for murder, this little toy. Go in like butter – absolutely like butter. Brought it with him, I suppose."

Battle shook his head.

"No. It was Mr. Shaitana's. It lay on the table near the door with a good many other knick-knacks."

"So the murderer helped himself. A bit of luck finding a tool like that."

"Well, that's one way of looking at it," said Battle slowly.

"Well, of course it wasn't luck for Shaitana, poor fellow."

"I didn't mean that, Doctor Roberts. I meant that there was another angle of looking at the business. It occurs to me that it was noticing this weapon that put the idea of murder into our criminal's mind."

"You mean it was a sudden inspiration? That the murder wasn't premeditated? He conceived the idea after he got here? Er – anything to suggest that idea to you?" He glanced at Battle searchingly.

"It's just an idea," said Superintendent Battle stolidly.

"Well, it might be so, of course," said Doctor Roberts slowly.

Superintendent Battle cleared his throat.

"Well, I won't keep you any longer, Doctor. Thank you for your help. Perhaps you'll leave your address."

"Certainly. Two hundred Gloucester Terrace, W. two. Telephone Bayswater No. two-three-eight-nine-six."