He looked in the artist’s face—it was flushed and eager and angry—evidently he had not missed the letter up to now.

“My dear sir, does it belong to you?” asked the detective, quietly.

“It does, sir.”

“Then take your property.”

“Very good, sir; but I have a right to ask, yes, demand of you, to explain under what peculiar circumstances this document chanced to come into your possession.”

“I do not question your right to ask that, and I shall readily tell where and when I picked the letter up.”

So he gave the time and place to a dot, but did not say anything about having seen it drop from the pocket of the owner. Prescott remembered that this was when and where he had received the message, and he had no doubt of the truth of the story.

At the same time he looked at the man by his side with a frown.

“You read this?” he asked.

“Naturally so—you could not blame me.”