assailant

“Before going into this, I would draw your attention to the fact that, if Alec Cunningham’s narrative was correct, and if the assailant, after shooting William Kirwan, had instantly fled, then it obviously could not be he who tore the paper from the dead man’s hand.

At this unusual sound, a huge black dog came rushing to meet the daring assailant of his ordinarily tranquil abode, snarling and displaying his sharp white teeth with a determined hostility that abundantly proved how little he was accustomed to society.