principal in the first degree

The perpetrator of a crime. — Also termed first-degree principal. [Cases: Criminal Law 61, 78. C.J.S. Criminal Law §§ 130, 143–144, 148.]

principal in the first degree 〈美〉一级主犯即亲自实施犯罪的人；或亲手或使用工具或利用不知情的第三人实施犯罪的共同犯罪人。