We may add that his mood was also inattentive.

He was not only unapprehensive of present danger, but his thoughts were naturally yielded to the condition of the two poor women, in that lonely abode of forest, whom he had just rescued, in all probability, from a fearful death.

Happy with the pleasant consciousness of a good action well performed, and with spirits naturally rising into animation, freed as they were from a late heavy sense of danger--he was as completely at the mercy of the outlaw who awaited him, pistol in hand, as if he lay, as his poor friend, Forrester, so recently had done, directly beneath his knife.
And so thought Rivers, who heard the approaching footsteps, and now caught a glimpse of his approaching shadow.
The outlaw deliberately lifted his pistol.

It was already cocked.

His form was sheltered by a huge tree, and as man and horse gradually drew nigh, the breathing of the assassin seemed almost suspended in his ferocious anxiety for blood.
The dark shadow moved slowly along the path.