The nominal adjective "innocent" may be translated "innocent person." The word "blood" is a metaphor for the violent death of the innocent person and a metonym for the person himself. Alternate translation: "they declare the innocent person guilty and then kill him" (See: [[rc://en/ta/man/jit/figs-nominaladj]] and [[rc://en/ta/man/jit/figs-metaphor]] and [[rc://en/ta/man/jit/figs-metonymy]])