"Did you notice me fingering this just now?" he asked anxiously.
Garth shook his head.
"Then take it, and, when the time comes, play with it that way yourself. Scratch your instructions on it with a match, a toothpick, anything handy. It will stay white, but I can make whatever you put on it as visible as headlines in a war extra. You'll reach town after ten. I'll hold back instructions until eleven in case these fellows have any spies in the department. But after that you can drop it near a uniformed policeman with a fair chance of its reaching me."
"You'll try to trail us, too?" Garth asked.
The inspector grinned sheepishly.
"Of course I'll try. I'll probably have to let it go at that."
"Yes—slippery," Garth answered.
Now that his offer was accepted, and his plan understood, the inspector gave way to a disquieting nervousness. He stood up and stepped around the desk, putting his hand on Garth's shoulder.
"Watch out for yourself," he faltered. "I don't want another Kridel case on my conscience."
The name dampened Garth's enthusiasm. He had never known Joe Kridel who, a year ago, had been the ascending star of the bureau. But the manner of the young man's death was depressingly familiar to him—found stabbed through the heart in a private house whose dwellers had heard no alarm. The key to that puzzle had never been discovered. Even the inspector had harbored the nature of Kridel's assignment that night of his murder.