"Perhaps," he returned, clearing up the materials which he had been using.
The telephone rang.
"Hello, Norton," I heard Craig answer. "What's that? You are shadowed by some one—you think it is by Whitney?"
I had been expecting something of the sort, and listened attentively, but it was impossible to gather the drift of the one-sided conversation.
As Kennedy hung up the receiver I remarked, "So it was not a bluff, after all."
"I think my plan is working," he remarked thoughtfully. "You heard what he said? He guesses right the first time, that it is Whitney. The last thing he said was, 'I'll get even! I'll take some action!' and then he rang off. I think we'll hear something soon."
Instead of going out, Kennedy pulled out the several unsigned letters we had collected, and began the laborious process of studying the printing, analyzing it, in the hope that he might discover some new clue.
XVI
THE EAR IN THE WALL
Perhaps an hour later our laboratory door was flung open suddenly, and both Kennedy and I leaped to our feet.