Why a thief is caught redhanded and not black blue or other clour?

Question

Why a thief is caught redhanded and not black blue or other clour?

Answer 1

The word red-handed originated from the notion of having been caught with blood on one's hands, that is, the person was guilty of committing a crime. Hence the term "red-handed" since blood cannot be be black, blue or other color  :-)

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