“The longer it was before the body was found, the more difficult it would be to fix the time of death accurately. If Miss Holland, for instance, fell over the body as soon as she came in, a doctor might be able to fix it within ten minutes or so—which might be awkward for our lady friend.”

I said, frowning:

“But if Agnes were suspicious of this person—”

Nash interrupted me.

“She wasn’t. Not to the pitch of definite suspicion. She just thought it ‘queer.’ She was a slow-witted girl, I imagine, and she was only vaguely suspicious with a feeling that something was wrong. She certainly didn’t suspect that she was up against a woman who would do murder.”

“Did you suspect that?” I asked.

Nash shook his head. He said, with feeling:

“I ought to have known. That suicide business, you see, frightened Poison Pen. She got the wind up. Fear, Mr. Burton, is an incalculable thing.”

“Yes, fear. That was the thing we ought to have foreseen. Fear—in a lunatic brain….

“You see,” said Superintendent Nash, and somehow his words made the whole thing seem absolutely horrible. “We’re up against someone who’s respected and thought highly of—someone, in fact, of good social position!”

III

Presently Nash said that he was going to interview Rose once more. I asked him, rather diffidently, if I might come too. Rather to my surprise he assented cordially.

“I’m very glad of your cooperation, Mr. Burton, if I may say so.”

“That sounds suspicious,” I said. “In books when a detective welcomes someone’s assistance, that someone is usually the murderer.”

Nash laughed shortly. He said: “You’re hardly the type to write anonymous letters, Mr. Burton.”

He added: “Frankly, you can be useful to us.”

“I’m glad, but I don’t see how.”

“You’re a stranger down here, that’s why. You’ve got no preconceived ideas about the people here. But at the same time, you’ve got the opportunity of getting to know things in what I may call a social way.”

“The murderer is a person of good social position,” I murmured.

“Exactly.”

“I’m to be the spy within the gates?”

“Have you any objection?”

I thought it over.

“No,” I said, “frankly I haven’t. If there’s a dangerous lunatic about driving inoffensive women to suicide and hitting miserable little maidservants on the head, then I’m not averse to doing a bit of dirty work to put that lunatic under restraint.”

“That’s sensible of you, sir. And let me tell you, the person we’re after is dangerous. She’s about as dangerous as a rattlesnake and a cobra and a black mamba rolled into one.”

I gave a slight shiver. I said:

“In fact, we’ve got to make haste?”

“That’s right. Don’t think we’re inactive in the force. We’re not. We’re working on several different lines.”

He said it grimly.

I had a vision of a fine far-flung spider’s web….

Nash wanted to hear Rose’s story again, so he explained to me, because she had already told him two different versions, and the more versions he got from her, the more likely it was that a few grains of truth might be incorporated.