Mr. Marshall answered.

"Six or seven of us were on the porch, the rest of us were inside, finishing breakfast. McGuire was just coming up from the lake, he had been out. The rock, without any warning, came down. Poor Sam.

He always sat where he could see the rock. It had a fascination for him. He always alluded to the possibility of its coming down."

Charles Rochambeau leaned forward in his chair tensely.

"Well, Professor, you could not save us from this could you?" He sprang up and threw his hands up with true Gallic violence. "My G.o.d, when will this end?"

There was pain, grief in the deep-set eyes that looked at the excitable old man. Professor Brierly said slowly:

"It will end right now, Mr. Rochambeau. It has ended." He turned to the two officers who had come with him, saying:

"A man by the name of Amos Brown, who lives about six miles up the lake was shot to death this morning."

Bruce Thomas started forward, crying hoa.r.s.ely:

"No, no. Amos Brown died thirty years ago."

Professor Brierly, ignoring the interruption, pointed at former Police Commissioner McGuire. "This man, officer, probably is armed. You will find that the bullet that killed Amos Brown came from his weapon."

One of the officers took a step toward the ruddy octogenarian.

Jimmy stared, startled. Something was coming off that he did not understand. Three of the men sprang to their feet glaring at the princ.i.p.al actors to this strange scene. McGuire stood up, the blood gradually draining from his face. One of the police officers asked quietly, holding out his hand:

"Are you armed, sir?" As McGuire's hand slowly went toward his side pocket, the officer said:

"Give me the weapon, please."

McGuire stared a long time at Professor Brierly, at his comrades, at the officers. He said:

"Yes, I killed Brown. I killed him in self-defense." He drew out the weapon, slowly.

Professor Brierly's voice, in the strained silence that had fallen on the group, sounded like a death knell.

"You did not kill Goldberg and Tonti in self-defense. You did not engineer the killing of Schurman, Miller and Flynn in self-defense.

You--_John!_" Professor Brierly's voice suddenly rose to a hoa.r.s.e shout. The weapon in the hand of the stout, erect, pale man was slowly turning. Matthews sprang forward, but the officer reached McGuire first. There was a brief struggle for the weapon.

Two officers led the man away.

There was pain in Professor Brierly's eyes, and not the exhilaration to be found at the successful conclusion of an experiment in science; or the completed solution of a crime. He sat down and appeared reluctant to furnish the explanation that was expected of him. Suddenly Justice Higginbotham burst out:

"But this is unthinkable, Professor. He was a comrade of ours. He was here with us all the time. He--you must be mistaken." He stopped and then continued more slowly, gravely:

"Professor Brierly, you will have to give a very good reason for your astounding charge. You will have to remove every reasonable doubt. I am not talking in the legal sense now. This man was our comrade. I should as soon believe that I did this impossible, this terrible thing myself."

A swift glance about the circle of faces showed Jimmy that they were all of the same mind. Professor Brierly said:

"I understand. That is why I was reluctant to make the charge sooner, when we discussed it the other day. Some of you urged me, remember, to make a guess, which I could have done then. This terrible thing that happened this morning is something I could hardly foresee." He paused and went on.

"Your number '14' Amos Brown died twenty-eight years ago, being survived by a son and grandson. The son died a short time later.

Amos Brown the third, had no kin. But he was a self-sufficient youngster who managed pretty well. He entered the flying service in the World War and returned a bitter, disillusioned man.

"He became a hatter and worked in Danbury, Connecticut, for a time, in a department called the 'pouncing' department. In such a department, they shave off the rough fur of felt hats after they have been dyed. In a 'pouncing' room, although there are blowers to take up the fine fur, there is nevertheless a good deal of it flying about in the air. I am thus dwelling on this seemingly trivial point because it formed an important clue in my investigation.

"Several years ago, young Amos Brown was approached by a man who was alleged to have been a comrade of his grandfather in the Civil War. Amos Brown was persuaded that your Tontine group had treated his grandfather very badly. He was shown that by working with this old veteran he could not only revenge his grandfather's wrongs, but also obtain a false justice for himself.

"This kind benefactor, as an evidence of goodwill, bought Amos Brown a farm in Canada; he bought him a plane. He then convinced him that by helping kill off the Tontine group the two of them would share their huge fund.

"Preparations were carefully made. Amos Brown was a strong, active man. The veteran had access to files where the peculiarities of a great many criminals, in and out of prison, were carefully recorded. It was recorded for example that one man had the habit of getting into places by using climbing irons. Another had a different method but he had a weakness for large quant.i.ties of food when he committed a robbery, his special weakness being for eggs. It was comparatively easy for a former police commissioner to get all this information you see, a police commissioner who kept in touch with his old department.

"But first of all the murders had to be so committed that they would look like suicide. The former man hunter knew enough to make them look like suicides to the casual examiner. But suppose a careful examination were made of a particular death, and it was discovered to be murder. Then what?

"Then you see, the peculiarities of a certain criminal would appear so prominently that the police would pick this man up and pin the crime on him. But suppose again this innocent criminal happened to have an unshakable alibi? That could be arranged for too. The alibi could be made to look 'fishy', as my friend Hale would put it.

"Former Police Commissioner McGuire knew that 'Chicago' Boyle, alias 'Lefty' Harris was in this neighborhood. 'Lefty' had been convicted of entering a house with rope, climbing irons, and so forth. So first of all, Miller was killed in a manner that would look to the casual examiner like suicide. When I pointed out that it was not suicide and further pointed out how the murderer entered, it was a foregone conclusion that Boyle would be picked up.

"Boyle had a story, but what policeman or jury would believe it?

The stranger who met him in a speakeasy and drugged his drink took good care that he would not have a convincing one to tell.

"The one flaw in the reckoning of the murderer was that the rope, with which entry was made, was found. It showed me as definitely as though I had seen it, the farmyard where Amos Brown lived. The twine also showed me that it had been in a 'pouncing' room in a hat factory for a long time.

"Boyle's watch which had not been cleaned for a long time and which we placed was in his possession about three years ago did not show that it had ever been in a 'pouncing' room. And you can depend on it, that one could not keep a watch for a single day in such a room without the fur getting inside the case, to say nothing of keeping it there for months or years.

"In the Schurman case, in New York, there was the fortuitous incident of the apple. Amos Brown was not a trained criminal, you see. He did not think, when he bit into the apple that he was leaving what the police call a 'calling card'. It will be found on investigation that Amos Brown's teeth fit into the 'moulage' of the apple.

"In addition to that, unfortunately for the murderer, 'Fingy' had a splendid alibi, an alibi that the killer could not foresee."

"The Flynn murder was easy. The man who made the telephone call need not have known what he was doing. But it is safe to say that it was Brown. Mr. McGuire would trust as few persons as possible in this. The call that killed Flynn might just as well have been made from Canada."

"But, Professor, you accused him of murdering Goldberg and Tonti,"

protested Judge Fletcher.

"Yes. Justice Higginbotham was going to make a spectacle of his mastery of a hobby. He had everything arranged. He was going to--"

"I had the wires disconnected, Professor, interrupted Judge Higginbotham."

"Connecting the wires would be just about a minute's work."

"But McGuire was down near the water. How could he throw a beam of light at that tube in the daylight."

"That's right, Judge. McGuire was facing the east. The sun was just right to reflect a powerful beam of sunlight into the door to the photo-electric cell with a piece of mirror. If you will look, Judge, you will find that door open.

"The act before that was the kidnapping of Matthews' nephew.

Brown, inherently a decent chap, balked at that but he was too involved by then. When they could not make me go to New York, Brown was told to send us a tooth as evidence of what they were prepared to do to the little boy. Brown balked at that too. He obtained some older boy's tooth, probably from a dentist."

He was now speaking more slowly.

"Obviously an octogenarian could not commit these murders himself, but being a former police commissioner, he could easily hire someone to do it for him; he knew the ropes. He could not trust the ordinary killer; he would have placed himself in such a man's power.

"What better instrument than Amos Brown? Amos Brown could be made to believe that he was performing an act of justice by killing the men who had mistreated his grandfather. Such a man is much more dangerous than the professional killer. He was a flyer and a good one. He had a powerful, fast plane, small enough not to attract too much attention. He could kill Schurman in the evening and Miller, four hundred miles away early the following morning.