Rosser was a sergeant in the United States Army. He was a superior of Harry Bosch in the late-1960s, at which time he ordered Bosch, who had the words HOLD FAST tattooed across his knuckles, to repeatedly punch a brick wall until the skin of his knuckles scarred over. Rosser did not like the phrase because it was a popular Navy saying. Bosch had learned it from San Pedro fishermen.