Definition of Accessory (legal term)

An accessory is a person who assists in the commission of a crime, but does not actually participate in the commission of the crime as a joint principal. The distinction between an accessory and a principal is a question of fact and degree:

• The principal is the one whose acts or omissions, accompanied by the relevant mens rea, are the most immediate cause of the actus reus (Latin for "guilty act").
• If two or more people are directly responsible for the actus reus, they can be charged as joint principals (see common purpose). The test to distinguish a joint principal from an accessory is whether the defendant independently contributed to causing the actus reus rather than merely giving generalised and/or limited help and encouragement.