At the same time, the detective's attitude towards the lawyer underwent a considerable change.

His professional caution, amounting almost to suspicion, became modified by the more perceptive point of view that as the dead man had turned to Mr.Brimsdown for assistance, it would be better for him to trust the lawyer also--to look upon him as an ally, and make common cause with him in the search for Robert Turold's murderer.
This changed attitude, carrying with it a seeming friendliness, the establishment, as it were, of an understanding between them, was not lost upon Mr.Brimsdown.But it had its awkward side for him, by giving added weight to the responsibility of deciding whether he should reveal or withhold his chance encounter with Sisily at Paddington.

Till then, Mr.
Brimsdown had been unable to make up his mind about that.

There were some nice points involved in the decision.

In an effort to reach a solution he broached the subject.
"Is it still your opinion that Miss Turold is guilty--after this letter ?" he asked.
"Her disappearance lays upon her the obligation of explaining her secret visit to her father on the night of the murder," was the guarded reply.
"Then you intend to arrest her ?" "Yes." "Do you know where she is ?" A quick consideration of this question led Barrant to the conclusion that it would do no harm to let the lawyer know the scanty truth.
"She is in London.