as replacing a pane of glass and
using putty colored like old putty.

"A very, very dangerous murderer and a very clever one, but hardly
a subtle one."

He turned to Brasher. "Now, young man, the rest ought to be simple
police work. Find a man in possession of twine and rope, on which
you will find adhering bits of brick, cement and paint, from
Miller's roof. Find him in possession of a pair of spurs, on which
you may find adhering bits of cement and you have your murderer."

As Brasher, thanking him effusively, was about to go. Professor
Brierly detained him.

"Just a moment. I want to send a telegram to New York. Leave this
at the telegraph office for me, please."

He turned to his companions as Brasher departed; he smiled
whimsically:

"Since you insist on plunging me into these things, I might as
well be prepared. I wired for several things that we may need
before this is over."

McCall was knitting his brow. He had followed with glowing
admiration the exposition of the old savant.

"Professor," he asked, "you say the murderer is a clever one, but
hardly a subtle one. Why do you say that?"

Professor Brierly dropped wearily into a deep chair on the porch.
He shuffled the sheets of paper each with its bullet hole
surrounded by powder marks.

"A man who kills another, usually uses the tools he knows best;
frequently he uses the tools of his trade. That is easiest;
following the lines of least resistance. Or, if killing becomes
his profession, he adopts and adapts certain tools for his
purpose, with which he becomes familiar.

"Just see how this murder was accomplished. A professional need
not be ashamed of the way the pane of glass was inserted, the use
of the rope, the climbing irons, or the spurs. The man who did
this has used all these materials and tools before.

"Even in this country, where we are far behind certain European
countries in such matters, it should be a simple matter for the
police to pick up the killer. They can go through their records
for the men who are accustomed to rob houses this way. They may
find half a dozen in their files. They will pick up all of them
who are not in prison and pin this murder on the guilty person.
The others will have adequate alibis.

"It must be obvious to you, of course, that though Miller's safe
was rifled, robbery was not the real motive for the entrance; it
was murder. It must also be obvious that no eighty-two-year-old
man could have done this.