ld Becker," said the under-detective, "though he went
by many aliases. He was a wandering sort of scamp, and is known to have
been in America; so that was where Brayne got his knife into him. We
didn't have much to do with him ourselves, for he worked mostly in
Germany. We've communicated, of course, with the German police. But,
oddly enough, there was a twin brother of his, named Louis Becker,
whom we had a great deal to do with. In fact, we found it necessary to
guillotine him only yesterday. Well, it's a rum thing, gentlemen, but
when I saw that fellow flat on the lawn I had the greatest jump of my
life. If I hadn't seen Louis Becker guillotined with my own eyes,
I'd have sworn it was Louis Becker lying there in the grass. Then, of
course, I remembered his twin brother in Germany, and following up the
clue--"

The explanatory Ivan stopped, for the excellent reason that nobody was
listening to him. The Commandant and the doctor were both staring at
Father Brown, who had sprung stiffly to his feet, and was holding his
temples tight like a man in sudden and violent pain.

"Stop, stop, stop!" he cried; "stop talking a minute, for I see half.
Will God give me strength? Will my brain make the one jump and see all?
Heaven help me! I used to be fairly good at thinking. I could paraphrase
any page in Aquinas once. Will my head split--or will it see? I see
half--I only see half."

He buried his head in his hands, and stood in a sort of rigid torture
of thought or prayer, while the other three could only go on staring at
this last prodigy of their wild twelve hours.

When Father Brown's hands fell they showed a face quite fresh and
serious, like a child's. He heaved a huge sigh, and said: "Let us get
this said and done with as quickly as possible. Look here, this will
be the quickest way to convince you all of the truth." He turned to the
doctor. "Dr. Simon," he said, "you have a strong head-piece, and I heard
you this morning asking the five hardest questions about this business.
Well, if you will ask them again, I will answer them."

Simon's pince-nez dropped from his nose in his doubt and wonder, but
he answered at once. "Well, the first question, you know, is why a man
should kill another with a clumsy sabre at all when a man can kill with
a bodkin?"

"A man cannot behead with a bodkin," said Brown calmly, "and for this
murder beheading was absolutely necessary."

"Why?" asked O'Brien, with interest.

"And the nex