The Colonel glanced at Dawson, but it was Freddy Farmer who asked the question. "If this skunk chap is still aboard the Indian, sir," he said slowly, "and if the aircraft carrier is to put to sea the day after tomorrow, what harm _can_ be done by that chap? Do you believe that while at sea he will make some effort to get in touch with Japanese forces? And is our job to stop him from doing that?" The senior officer thought over the answer to that for a moment, and scowled hard at the opposite wall. "The best answer to that," he finally said, "is what I told you a moment ago. I mean that I can see that you are put aboard the Indian, but from then on you are absolutely on your own. Frankly, you will be doing no more than punching in the dark. I feel certain that the spy is still aboard, but _I don't know for sure_. If he is aboard, and the Indian puts to sea, the information he has collected may be just a beautiful white elephant on his hands. He may not be able to do a single thing about it until it is too late, and his information not be worth a darn. But the point is, we can't take chances on anything. "You see, we have no idea whether our man is a seaman, a mechanic, or a flying officer. Suppose for a minute that he is a flying officer. Think of the opportunities he'd have to contact the Japs. On patrol he could sneak a message over the side that would drop down to be picked up by a Jap submarine. He might even break formation and scoot off to some point where he knows Japs naval vessels are on patrol, and contact them that way. He might not even return. No, Farmer, the fact that he goes to sea with the Indian doesn't make anything certain for us." The senior officer paused, looked very unhappy, and sighed heavily. "That is the rotten part of Intelligence work," he grunted presently. "Nine cases out of ten you have absolutely nothing to work on. You've just got to make blind stabs in the dark, and trust that you'll connect with something that will get you somewhere. The only suggestion I can give you is to keep your eyes and ears open every minute of the time--particularly your eyes. It seems certain that the murderer isn't going to keep his secret any longer than he has to. It's plain dynamite, and he knows it. He's going to try somehow to get that knowledge to the Japanese Fleet. If you can spot him and nail him, you will be everlastingly blessed by the Navy, from the President on down." "Well, we'll do our best," Dave said grimly. "And I hope and pray it will be good enough." "Amen, to that," Colonel Welsh said softly. Then, pushing up onto his feet, he said, "Well, we can start now by finding you two uniforms that don't look as if they were picked out in the dark. Then we'll go on out to Alexandria Field--and head west." CHAPTER SIX _Midnight Menace_