ACCOMPLICE (from Fr. complice, conspirator, Lat. complex, a sharer, associate, complicare, to fold together; the ac- is possibly due to confusion with "accomplish," to complete, Lat. complere, to fill up), in law, one who is associated with another or others in the commission of a crime, whether as principal or accessory. The term is chiefly important where one of those charged with a crime turns king's evidence in the expectation of obtaining a pardon for himself. Accordingly, as his evidence is tainted with self-interest, it is a rule of practice to direct a jury to acquit, where the evidence of an accomplice is not corroborated by independent evidence both as to the circumstances of the offence and the participation of the accused in it. An accomplice who has turned king's evidence usually receives a pardon, but has no legal right to exemption from punishment till he has actually received it.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)