The fourth was Mr.E.van Cortlandt Wynne.

In the seclusion of his home in Thirty-seventh Street, Mr.Wynne read the story with puckered brows, then re-read it, after which he paced back and forth across his room in troubled thought for an hour or more.

An oppressive sense of uneasiness was coming over him; and it was reflected in eyes grown somber.
After a time, with sudden determination, the young man dropped into a chair at his desk, and wrote in duplicate, on a narrow strip of tough tissue-paper, just one line: Are you safe?
Is all well?
Answer quick.
W.
Then he mounted to the roof.

As he flung open the trap a man on the top of the house next door darted behind a chimney.

Mr.Wynne saw him clearly--it was Frank Claflin--but he seemed to consider the matter of no consequence, for he paid not the slightest attention.
Instead he went straight to a cage beside the pigeon-cote, wherein a dozen or more birds were imprisoned, removed one of them, attached a strip of the tissue-paper to its leg, and allowed it to rise from his out-stretched hand.
The pigeon darted away at an angle, up, up, until it grew indistinct against the void, then swung widely in a semicircle, hovered uncertainly for an instant, and flashed off to the west, straight as an arrow flies.