“It’s an idea,” Marshall admitted. “I can see where there’s going to be some advantage in having a psychologist among the witnesses. But there’s another witness I’m even more anxious to—” His face lit up as Sergeant Raglan came in. “She’s here, Rags?”

“Yeah,” said Raglan. “It’s the sister. Holy smoke, Loot, does this mean this is gonna be another screwy one?”

Marshall had said she and Raglan had said the sister. These facts may serve as sufficient characterization of Sister Felicitas, who had accompanied her. They were always a pair, yet always spoken of in the singular. Now Sister Felicitas dozed in the corner where the hunchback crouched, and Marshall read and reread the letter which seemed like the posthumous utterance of the Stripper’s latest victim:

My dear Sister:

I have reason to fear that someone close to me is Jack the Stripper.

You know me, I trust, too well to think me a sensationalist striving to be a star witness. I have grounds for what I say. This individual, whom I shall for the moment call “Quasimodo” for reasons that might particularly appeal to you, first betrayed himself when I noticed a fleck of blood behind his ear—a trifle, but suggestive. Since then I have religiously observed his comings and goings, and found curious coincidences between the absence of Quasimodo and the presence elsewhere of the Stripper.

I have not a conclusive body of evidence, but I believe that I do have sufficient to bring to the attention of the authorities. I have heard you mention a Lieutenant Marshall who is a close friend of yours. If you will recommend me to him as a man whose word is to be taken seriously, I shall be deeply obliged.

I may, of course, be making a fool of myself with my suspicions of Quasimodo, which is why I refrain from giving you his real name. But every man must do what is possible to rid this city a negotio perambulante in tenebris.

Yours respectfully,

Harvey Flecker

“He didn’t have much to go on, did he?” Marshall observed. “But he was right. God help him. And he may have known more than he cared to trust to a letter. He must have slipped somehow and let Quasimodo see his suspicions. . . . What does that last phrase mean?”

“Lieutenant! And you an Oxford man!” exclaimed Sister Ursula.

“I can translate it. But what’s its connotation?”

“It’s from St. Jerome’s Vulgate of the ninetieth psalm. The Douay version translates it literally: of the business that walketh about in the dark; but that doesn’t convey the full horror of that nameless prowling negotium. It’s one of the most terrible phrases I know, and perfect for the Stripper.”

“Flecker was a Catholic?”