the prison guard says:
"And what are you? A spic? A gypsy?"
"Not that I know of, sir. Maybe."
The guard goes on to suggest:
"Maybe you got nigger blood in you.
"Could be, sir."
Sam thinks that he looks native american:
"You got Indian blood in you?"
"Not that I know of."
"You looked like it, was all."
Later there's a reference to his cream-and-coffee skin:
. . . here he was, a large, clumsy sixteen-year-old with acne pocking his cream-and-coffee skin . . .