“Who are they?” inquired Boyd quickly. “Tell me all you know concerning them, as we are about to prosecute inquiries in their direction.”

“First, tell me the statement of the house owner,” I said.

“Well, he describes Mrs Blain as a middle-aged, rather pleasant lady, who came to his office about a year ago in response to an advertisement in the Morning Post. She appeared most anxious to have the house, and one fact which appears to strike the old fellow as peculiar is that she took it and paid a ten-pound note as deposit without ever seeing the interior of the premises. She told him that it was for some friends of hers from abroad, and that they not having arrived she would sign the agreement and accept all responsibility.”

“Anything else?”

“Yes,” the detective replied. “She was accompanied by a young lady, whom old Tritton, the landlord, took to be her daughter. Now, tell me what you know.”

I paused, looking at him fixedly. The disclosure that Mrs Blain was the actual holder of that house of mystery was certainly startling. It was remarkable, too, that on the very night of the crime I should receive a letter from Mary, the woman who had so long lingered in my memory. Was that, I wondered, anything more than a mere coincidence?

“I don’t know that I can tell you very much about the family,” I answered, determined to put him off the scent and make inquiries myself. “They were much respected when at Shenley, where they kept up a fine country house, and entertained a great deal. They were parishioners of my father, therefore I went there very often.”

“Do you know Mrs Blain well?”

“Quite well.”

“And her daughter?” suggested Dick, much interested. “What’s she like? Pretty?”