“What’s a rabbit gun?” I asked.
“A rabbit gun is a small brass twenty-two-caliber rifle attached to a log by a screw. The bait is carried on a wire attached to the trigger, the bait being in front of the muzzle, and when the rabbit takes the bait, the gun is fired and hits the rabbit in the head. But what makes your discovery exciting is this. We have evidence that Leroy Brady was taking one of these guns apart on his bench about two weeks before the murder”.
“Did you ask him why he had been doing that?”
“Yes”, they answered. “Leroy said he was taking it apart to remove the steel trigger and replace it with a brass one, because he was afraid the steel trigger would rust, out in the woods”.
“That’s nonsense”, I said. “Any good mechanic would know that a brass trigger wouldn’t work. The sharp, nicked edge which holds back the cocked hammer would wear away in no time with soft metal like brass”.
I told the police that in my opinion, Leroy had taken the rifle apart to find out how the internal mechanism operated. I asked them to find and bring me the rifle if they could. I said it would probably have a brass trigger on it by now all right, since he wouldn’t be fool enough not to put one on when he had a chance. In the meantime I realized that to make a case, we must find out if possible what the steel tubing had originally been made for and where it had come from. It had evidently been a gas-welded tube of commercial factory manufacture. Remembering, in this case, that the Wall Street bomb fragments had never been successfully traced, I decided to take on this search myself. I began by visiting personally a number of big hardware stores and showing them the fragments. They told me the tubing was not standard gauge and must be of foreign make. This did not satisfy me. I next wrote to the editor of Iron Age, the New York metallurgical journal, asking him to send me the addresses of all companies in the United States which manufactured gas-welded steel tubing. He gave me the addresses of seven or eight companies, and I mailed a fragment of the tubing to the first company listed, asking them to send it to the next on the list, and so on until it could be identified. It became a sort of chain letter. The first three companies to which it went could not identify it. But the fourth, the Republic Steel Corporation, replied, “We recognize this tubing as our manufacture. It is a bastard size and is made to order for General Motors to serve as the torque rod of the steering gear of the Chevrolet”. The torque rod runs down the steering post, from the lever which advances and retards the throttle.
So the tubing in the bomb had definitely come from a Chevrolet garage or storeroom! Dr. Wood was making progress. But there were thousands of Chevrolet garages — hundreds in Maryland and the District of Columbia. It remained to be proven, if possible, that this particular tubing had come from the one garage where Leroy Brady worked. It seemed utterly impossible to do this. But our scientific detective in real life had made an additional microscopic discovery which might point the way.
Wood continues:
I had discovered a tiny, seemingly accidental imperfection, if you could call it that, in the tubing fragments — two parallel scratches, microscopically visible on all the fragments, along the tube’s seam — made probably by a nick on the machine which had polished them. I went to Chevrolet headquarters in Baltimore, first of all, and asked permission to examine the torque rods they had in stock. None of them showed similar scratches along the seams. I then asked Lieutenant Itzel to send someone quietly down to the Chevrolet garage in Washington where Leroy Brady worked, to purchase and bring back a couple of torque rods from the stock there. These were brought to me, and both of them had scratches identical with those on the bomb fragments, showing that they must have come from the same batch of material as the rod used in the construction of the bomb.
The net was closing in. My findings now pointed more and more definitely to Leroy Brady.
I was certain, from the remains of the small copper disk welded by the explosion to the fragment of steel cylinder which had been part of the mechanism, that an old-fashioned percussion cap identical with those used for muzzle-loading shotguns had been used. Furthermore, another fragment of like steel cylinder Lieutenant Itzel had later found showed that a skilled workman had “turned” its end down to exactly the right diameter to fit such a cap.
I felt this might form an additional clue, since muzzle-loading shotguns were extremely rare as late as 1930, even in rural districts. I wasn’t thinking any more about the twenty-two- caliber rabbit rifle which had merely supplied the model for the firing mechanism — but about where the shotgun cap had come from. The cap used in the bomb had been pure copper. I had Itzel buy several boxes of caps, each made by a different arms company, and analyzed the metal. All the types but one were made of brass, copper plated. Only the caps made by Remington were pure copper.
I was now ready to take a chance. I told Lieutenant Itzel to get a search warrant — to search the farm where Herman Brady lived, from attic to cellar, for a muzzle-loading shotgun, or for any evidence that there had been one there, and to look for a box of percussion caps. Three hours later he was back at my laboratory.
“Well, Doc”, he said, “we found the muzzle-loader, and we also found a box of percussion caps on the mantelpiece… and they were Remington!”
I said, “Bring them in, and I think I can promise you the material for an indictment and conviction of one or both of the boys”.
Lieutenant Itzel said, “Oh, we’ve got the shotgun all right, but we didn’t bring the caps along. We left them on the mantel”.
I sent the detectives back. But in the meantime the evidence had disappeared.
When District Attorney Ryan heard the story, he said: “Well, I guess, just the same, we can ask the Grand Jury for an indictment”.
“Not quite yet”, I said. “I want to make a firing mechanism exactly like that of the bomb, with similar tube, springs, steel plugs, percussion cap and everything, and then explode a stick of dynamite against it and see whether we cannot get an exact reproduction of the fragments”.
This was direct scientific experimental method, and the District Attorney had sense enough to approve it.
I asked Lieutenant Itzel to obtain the dynamite and arrange a place where we could go out into the country to try it.
In the meantime I had learned that a spring similar to the one used in the bomb was used in the manufacture of the door-handle mechanism of Chevrolet cars. From a piece of identical spring, therefore, from a piece of tube cut from that bought from the garage in Washington, and from a piece of steel cylinder obtained in our own Johns Hopkins machine shop, I made a model of the mechanism as I conceived it.
Next day I was driven in a police car out into the country, to the place of a man who sold dynamite. Behind the house was a shed in which he kept the dynamite and detonators. We cut off half a stick, attached my model of the firing mechanism to it, dug a hole in the ground, placed the combination at the bottom, covering it over with a large box, lighted a fuse, retreated to a distance, and let it explode. Digging in the earth at the bottom of the hole, we discovered the wreckage of the firing mechanism which I had made. In every way it was identical with the wreckage of the firing mechanism of the original bomb. Everything had been exactly reproduced, including the flattening of the tube, the spiral grooves on the inside, and the U-shaped hooks formed by the fractures of the coils of the spring.
The grand jury returned an indictment of both the brothers. The trial resulted in a hung jury, but at a second trial Leroy was convicted of second-degree murder and was given ten years. A good deal of the technical evidence had been ruled out, and he escaped the death penalty. Herman had been indicted as an accessory, but the case against him was dropped, despite the fact that he had accompanied Leroy when the bomb was delivered and the crime had obviously been committed to get him out of a jam… .