Culprit

An individual who has been formally charged with a criminal offense but who has not yet been tried and convicted.

Culprit is a colloquial rather than a legal term and is commonly applied to someone who is guilty of a minor degree of moral reprehensibility. According to SIR WILLIAM BLACKSTONE, the term is most likely a derivative of the archaic mode of ARRAIGNMENT during which upon a prisoner's plea of not guilty the cleric would say culpabilis prit, meaning "he is guilty and the crown is ready." The more common derivation is from culpa, meaning "fault or blame."