culprit
Concise Oxford English Dictionary © 2008 Oxford University Press:
culprit/ˈkʌlprɪt/
▶noun a person who is responsible for a crime or other misdeed.
■ the cause of a problem.
– origin C17: orig. in the judicial formula Culprit, how will you be tried?, perh. from a misinterpretation of the written abbrev. cul. prist for Anglo-Norman Fr. Culpable: prest d'averrer notre bille ‘(You are) guilty: (We are) ready to prove our indictment’.
'culprit' also found in these Oxford entries:
