realised that the cipher was known, and
went to the newspaper office to try and stop the insertion of the
advertisement that might enable us to find Grell. Of course she failed,
and we got a message which had been handed in by Petrovska. One of our
men followed her.

"We deciphered the message, and it enabled us to discover your
hiding-place on the river. But the business was muddled, and you got
away. We found the sheath of the knife used in the murder among other
belongings you left behind. By the way, we understand that that dagger
had belonged to Harry Goldenburg--how came it to be lying about your
room?"

Grell shook his head. "That is a mistake. The dagger was mine. It is
possible that he had a similar one."

"Yes, that is possible. But in the event, the point does not matter
much. What was more important was, that we had driven you out of a
secure hiding-place.

"Meanwhile, Pinkerton's had been hard at work on the other side of the
Atlantic, and many episodes of your private life were minutely examined.
Their detectives it was, too, who had discovered that Goldenburg and
Petrovska had in some way been associated with you. What they found out
pointed to blackmail. Here appeared an adequate motive for you to murder
Goldenburg."

Grell tapped impatiently on the table, but did not interrupt. Heldon
Foyle went on.

"We could not blind ourselves to the fact that you were not the type of
man who would commit an ordinary crime under stress of temptation. But
homicide is in a class by itself. You might have committed murder.
Indeed, there was the strongest possible assumption that you had done
so.

"You will observe that there was nothing miraculous in what we did. One
step led to another in natural sequence. On the barge, we got the letter
that led to the tracing of Ivan at the gambling-house in Smike Street.
We knew your finances were cramped. We were, as opportunity offered,
limiting your helpers, so that we might force you to show yourself.

"That is what happened. You went to Sir Ralph Fairfield, and succeeded
in dodging our men--so far. It was Fairfield's servant who gave you
away. He came to Scotland Yard and, in my absence, was taken away by Sir
Ralph. When I returned, I arranged to get Sir Ralph out of his chambers
for a time, sufficient to allow me a talk with his servant. I then
bluffed some idea of your mission out of Sir Ralph. I found you had been
refused money.

"You had already applied once t