The detective's face flushed.

"That will be enough from you, Mr. Sherlock Holmes," he said. "If you open your mouth again, I'll arrest you as a material witness and as a possible accomplice."

"That sounds like Chicago methods," said Carnes quietly. "Now listen to me, Captain. My a.s.sistant and I are merely trying to a.s.sist you in this case. If you don't desire our a.s.sistance we'll proceed along our own lines without interfering, but in the meantime remember that this is a National Bank, and that our questions will be answered. The United States is higher than even the Chicago police force, and I am here under orders to investigate a counterfeiting case. If I desire, I can seal the doors of this bank and allow no one in or out until I have the evidence I desire. Do you understand?"

Sturtevant sprang to his feet with an oath, but the sight of the gold badge which Carnes displayed stopped him.

"Oh well," he said ungraciously. "I suppose that no harm will come of letting Winston answer your fool questions, but I'll warn you that I'll report to Washington that you are interfering with the course of justice and using your authority to aid the getaway of a criminal."

"That is your privilege," replied Carnes quietly. "Mr. Winston, will you answer Mr. Berger's question?"

"Why, I asked him because he was right close to the money and I thought that he might have reached through the wicket and picked it up. Then, too--"

He hesitated for a moment and Dr. Bird smiled encouragingly.

"What else?" he asked.

"Why, I can't exactly tell. It just seemed to me that I had heard the rustle that bills make when they are pulled across a counter. When I saw them gone, I thought that he might have taken them. Then when I turned toward him, I seemed to hear the rustle of bills behind me, although I knew that I was alone in the cage. When I looked back the money was gone."

"Did you see or hear anything like a shadow or a person moving?"

"No--yes--I don't know. Just as I turned around it seemed to me that the rear door to my cage had moved and there may have been a shadow for an instant. I don't know. I hadn't thought of it before."

"How long after that did you ring the alarm gongs?"

"Not over a second or two."

"That's all," said Dr. Bird.

"If your high and mightiness has no further questions to ask, perhaps you will let me ask a few," said Sturtevant.

"Go ahead, ask all you wish," replied Dr. Bird with a laugh. "I have all the information I desire here for the present. I may want to ask other questions later, but just now I think we'll be going."

"If you find any strange finger-prints on Winston's counter, I'll be glad to have them compared with our files," said Carnes.

"I am not bothering with finger-prints," snorted the detective. "This is an open and shut case. There would be lots of Winston's finger-prints there and no others. There isn't the slightest doubt that this is an inside case and I have the men I want right here. Mr. Rogers, your bank is closed for to-day. Everyone in it will be searched and then all those not needed to close up will be sent away. I will get a squad of men here to go over your building and locate the hiding place. Your money is still on the premises unless these men slipped it to a confederate who got out before the alarm was given. I'll question the guards about that.

If that happened, a little sweating will get it out of them."

"Are you going to arrest me?" demanded Trier in surprise.

"Yes, dearie," answered the detective. "I am going to arrest you and your two little playmates if these Washington experts will allow me to.

You will save a lot of time and quite a few painful experiences if you will come clean now instead of later."

"I demand to see my lawyer and to communicate with my firm," said the paymaster.

"Time enough for that when I am through with you," replied the detective.

He turned to Carnes.

"Have I your gracious permission to arrest these three criminals?" he asked.

"Yes indeed, Captain," replied Carnes sweetly. "You have my gracious permission to make just as big an a.s.s of yourself as you wish. We're going now."

"By the way, Captain," said Dr. Bird as he followed Carnes out. "When you get through playing with your prisoners and start to look for the thief, here is a tip. Look for a left-handed man who has a thorough knowledge of chemistry and especially toxicology."

"It's easy enough to see that he was left-handed if he pulled that money out through the grill from the positions occupied by Trier and his guard, but what the d.i.c.kens led you to suspect that he is a chemist and a toxicologist?" asked Carnes as he and the doctor left the bank.

"Merely a shrewd guess, my dear Watson," replied the doctor with a chuckle. "I am likely to be wrong, but there is a good chance that I am right. I am judging solely from the method used."

"Have you solved the method?" demanded Carnes in amazement. "What on earth was it? The more I have thought about it, the more inclined I am to believe that Sturtevant is right and that it is an inside job. It seems to me impossible that a man could have entered in broad daylight and lifted that money in front of three men and within sight of a hundred more without some one getting a glimpse of him. He must have taken the money out in a grip or a sack or something like that, yet the bank record shows that no one but Trier entered with a grip and no one left with a package for ten minutes before Trier entered."

"There may be something in what you say, Carnes, but I am inclined to have a different idea. I don't think it is the usual run of bank robbery, and I would rather not hazard a guess just now. I am going back to Washington to-night. Before I go any further into the matter, I need some rather specialized knowledge that I don't possess and I want to consult with Dr. Knolles. I'll be back in a week or so and then we can look into that counterfeiting case after we get this disposed of."

"What am I to do?" asked Carnes.

"Sit around the lobby of your hotel, eat three meals a day, and read the papers. If you get bored, I would recommend that you pay a visit to the Art Inst.i.tute and admire the graceful lions which adorn the steps.

Artistic contemplations may well improve your culture."

"All right," replied Carnes. "I'll a.s.sume a pensive air and moon at the lions, but I might do better if you told me what I was looking for."

"You are looking for knowledge, my dear Carnes," said the doctor with a laugh. "Remember the saying of the sages: To the wise man, no knowledge is useless."

A huge Martin bomber roared down to a landing at the Maywood airdrome, and a burly figure descended from the rear c.o.c.kpit and waved his hand jovially to the waiting Carnes. The secret service man hastened over to greet his colleague.

"Have you got that truck I wired you to have ready?" demanded the doctor.

"Waiting at the entrance; but say, I've got some news for you."

"It can wait. Get a detail of men and help us to unload this ship. Some of the cases are pretty heavy."

Carnes hurried off and returned with a gang of laborers, who took from the bomber a dozen heavy packing cases of various sizes, several of them labelled either "Fragile" or "Inflammable" in large type.

"Where do they go, Doctor?" he asked when the last of them had been loaded onto the waiting truck.

"To the First National Bank," replied Dr. Bird, "and Casey here goes with them. You know Casey, don't you, Carnes? He is the best photographer in the Bureau."

"Shall I go along too?" asked Carnes as he acknowledged the introduction.

"No need for it. I wired Rogers and he knows the stuff is coming and what to do with it. Unpack as soon as you get there, Casey, and start setting up as soon as the bank closes."

"All right, Doctor," replied Casey as he mounted the truck beside the driver.

"Where do we go, Doctor?" asked Carnes as the truck rolled off.