Again the Chief interrupted him. "Oh! I haven't told you all my news yet, not by a long shot," he said. And again the head of the secret service rubbed his hands together. "We know who the driver of the wireless motor-car is. I don't mean we know the name he's using. Anybody could get that out of a directory. It's Sanders. But we know who he really is. And that's why we feel so good to-day. He's a man we've been looking for for months. He is one of the German agents implicated in the papers we seized in Wolf von Igel's office. The secret service has been more than anxious to discover his whereabouts. Now we have him, for he's under observation and cannot escape us.
"He came to this country about a year before the war started," continued the Chief, a gleam of satisfaction shining in his eyes, "and bought out an insurance agent who made a specialty of insuring suburban properties. From the beginning, he made a practice of visiting the properties that he insured. This took him about a good deal and gave him an excuse for being so much in a motor-car. Ah! What an ideal situation for a spy! Clever, aren't they?"
But the Chief gave his visitor no chance to reply to his query. Smiling again, he went on, "But even this is not all. Of course you understand, Captain, that your boys are not the only amateurs helping us out in this pinch. Ever since we became convinced that the Germans have a line of secret wireless stations by which they are relaying news to their agents in Mexico—for we're morally certain that is where these messages go—we've had trusted amateurs helping us just as you have helped us—by listening in. Some of them have been at it for weeks. When we could get no trace of secret messages along the direct route to Mexico, where they would naturally have their stations, we began to suspect that the Germans were using a round-about route in the hope of deceiving us completely."
"And you've located some of them?"
"Exactly. Your boys will tell you that yesterday was one of those days when radio communication is at its best—when an operator picks up sounds that at other times he could not possibly hear. The result was that we picked up yesterday's secret message at half a dozen different points. Where do you think the first one was?"
"Give it up."
"Buffalo—north instead of south. Clever, eh? Then we got it near Detroit, and Milwaukee, and Omaha, and Santa Fé. Finally one of our listeners picked it up at Socorro, a place about one hundred and seventy miles north of El Paso. Now we know the line of their stations. We'll set a regiment of amateurs to listening in along that line and we'll locate every station in it in no time. Then we'll grab all their agents at the same time in one big raid and wipe out this spy system for good."
"That is great news," said Captain Hardy, his eyes sparkling with interest. "Great! You certainly have cause to feel good."
"For a little while," replied the Chief, "I thought I had even more good news. But it proved to be a false alarm."
"What was it?" inquired Captain Hardy as the Chief stopped speaking.