“A letter!” he exclaimed. “They saw it flashing by; but no one saw it dropped into the chute. They called all the way down from the ninth floor.

“It must have been dropped at the tenth. The men are going up to see.”

The man from the post office was unlocking the mail box. Cardona was trying to regain his composure. He heard Biscayne talking excitedly to Weston and Fredericks.

He was telling them of the attempt on Arthur Wilhelm’s life. With such startling news announced, the three had no thought of the letter.

But Cardona was thinking of it. With Mayhew at his side, he was crowding toward the mail box.

THE man at the box brought out a letter. Its address was identical with those that had been received before. It was typed with capital letters.

Cardona seized the envelope. He ripped it open and pulled out the paper. He spread the sheet with shaking hands.

It bore a typed announcement, but Cardona’s eyes were unseeing so far as the typewritten words were concerned.

Across the center of the sheet, written in well-formed characters of bright-blue ink, were these words:

Annulled. By The Shadow.