And the thoughts which had come to Guillaume must have been very serious and very pressing, for he all at once began to retrace his steps and follow the workman from a distance, as if to ascertain for certain what direction he would take.
Pierre had watched the scene with growing disquietude.

His nervous apprehension of some great unknown calamity, the suspicions born of his frequent and inexplicable meetings with Salvat, his surprise at now seeing his brother mingled with the affair, all helped to fill him with a pressing desire to know, witness, and perhaps prevent.

So he did not hesitate, but began to follow the others in a prudent way.
Fresh perturbation came upon him when first Salvat and then Guillaume suddenly turned into the Rue Godot-de-Mauroy.

What destiny was thus bringing him back to that street whither a little time previously he had wished to return in feverish haste, and whence only the death of Laveuve had kept him?
And his consternation increased yet further when, after losing sight of Salvat for a moment, he saw him standing in front of the Duvillard mansion, on the same spot where he had fancied he recognised him that morning.

As it happened the carriage entrance of the mansion was wide open.