She had gone to Paris for one of two reasons, he concluded.

Either she had expected him to return thither from London, and had gone to meet him with the intention of coming to some arrangement as to the disposal of the vast sum of money now in Turner's hands awaiting further developments, or some hitch had occurred with respect to John Turner himself.
Dormer Colville returned, thoughtfully, to his lodging, and in the evening set out for Paris.
He himself had not seen Turner since that morning in the banker's office in the Rue Lafayette, when they had parted so unceremoniously, in a somewhat heated spirit.

But, on reflection, Colville, who had sought to reassure himself with regard to one whose name stood for the incarnation of gastronomy and mental density in the Anglo-French clubs of Paris, had come to the conclusion that nothing was to be gained by forcing a quarrel upon Turner.

It was impossible to bring home to him an accusation of complicity in an outrage which had been carried through with remarkable skill.

And when it is impossible to force home an accusation, a wise man will hold his tongue.
Colville could not prove that Turner had known Barebone to be in the carriage waiting in the courtyard, and his own action in the matter had been limited to the interposition of his own clumsy person between Colville and the window; which might, after all, have been due to stupidity.