good would that have done you? You wanted her
entire fortune, did you not? But that could have come to you only after
thirty years, and you are not likely to have waited that long. Your plan
was to murder your step-sister, even if you could not get a letter from
her telling of her intention to commit suicide."

Langen rose suddenly, but controlled himself again and sank back easily
in his chair. "Then the old woman has been talking?" he asked.

Muller shook his head. "We knew it through Miss Langen herself."

"She has spoken to no one for over ten days."

"But you let her throw her notebook out of the window of the cab."

"Ah--"

"There, you see, you should not have let that happen."

Drops of perspiration stood out on Langen's forehead. Until now,
perhaps, he had had some possible hope of escape. It was useless now, he
knew.

As calmly as he had spoken thus far Muller continued. "For twenty years
I have been studying the hearts of criminals like yourself. But there
are things I do not understand about this case and it interests me very
much."

Langen had wiped the drops from his forehead and he now turned on Muller
a face that seemed made of bronze. There was but one expression on it,
that of cold scorn.

"I feel greatly flattered, sir, to think that I can offer a problem
to one of your experience," Langen began. His voice, which had been
slightly veiled before, was now quite clear. "Ask me all you like. I
will answer you."

Muller began: "Why did you wait so long before committing the murder?
and why did you drag your victim from place to place when you could have
killed her easily in the compartment of the railway train?"

"The windows of the compartment were open, my honoured friend, and it
was a fine warm evening for the season, because of which the windows in
the other compartment were also open. There was nothing else I could
do at that time then, except to offer Asta a cup of tea when she felt a
little faint upon leaving the train. I am a physician and I know how to
use the right drugs at the right time. When Asta had taken the tea, she
knew nothing more until she woke up a day later in a room in the city."

"And the piece of paper with the threat on it? and the revolver you
left so handy for her? oh, but I forgot, the old woman took the weapon
away before the lady could use it in her despair," said Muller.

"Quite right. I see you know every detail."

"But why didn't you complete your crime i