Of course Hanaud might be wrong.

Only, if he were wrong, how had he come to suspect Harry Wethermill?
What had first directed his thoughts to that seemingly heart-broken man?
And when?
Certain recollections became vivid in Mr.Ricardo's mind--the luncheon at the Villa Rose, for instance.

Hanaud had been so insistent that the woman with the red hair was to be found in Geneva, had so clearly laid it down that a message, a telegram, a letter from Aix to Geneva, would enable him to lay his hands upon the murderer in Aix.

He was isolating the house in Geneva even so early in the history of his investigations, even so soon he suspected Harry Wethermill.

Brains and audacity--yes, these two qualities he had stipulated in the criminal.