d Mr. Minute," explained Mr. Wiseman. "It is what I
call a mystery within a mystery, and it has never been properly cleared
up. I thought something was coming out about it at the trial, but you
know what a mess the lawyers made of it."

It was Constable Wiseman's firm conviction that Frank Merrill had
escaped through the incompetence of the crown authorities, and there
were moments in his domestic circle when he was bitter and even
insubordinate on the subject.

"You still think Mr. Merrill was guilty?" asked Saul Arthur Mann as he
took his leave of the other.

"I am as sure of it as I am that I am standing here," said the
constable, not without a certain pride in the consistency of his view.
"Didn't I go into the room? Wasn't he there with the deceased? Wasn't
his revolver found? Hadn't there been some jiggery-pokery with his books
in London?"

Saul Arthur Mann smiled.

"There are some of us who think differently, Constable," he said,
shaking hands with the implacable officer of the law.

He brought back to London a few new facts to be added to his record of
Sergeant Crawley, alias Smith, and on these he went painstakingly to
work.

As has been already explained, Saul Arthur Mann had a particularly
useful relationship with Scotland Yard, and fortunately, about that
time, he was on the most excellent terms with official police
headquarters, for he had been able to assist them in running to earth
one of the most powerful blackmailing gangs that had ever operated in
Europe. His files had been drawn upon to such good purpose that the
police had secured convictions against the seventeen members of the gang
who were in England.

He sought an interview with the chief commissioner, and that same night,
accompanied by a small army of detectives, he made a systematic search
of Silvers Rents. The house into which Jasper Cole had been seen to
enter was again raided, and again without result. The house was empty
save for one room, a big room which was simply furnished with a
truckle-bed, a table, a chair, a lamp, and a strip of carpet. There were
four rooms--two upstairs, which were never used, and two on the ground
floor.

At the end of a passage was a kitchen, which also was empty, save for a
length of bamboo ladder. From the kitchen a bolted door led on to a tiny
square of yard which was separated by three walls from yards of similar
dimensions to left and right and to the back of the premises. At the
back of Silver