For many criminal law casesoffences, from what I understand, you have to establish 2 aspects: actus reus (the act of crime), and mens rea (the guilty mind). The mens rea can be many things: from as direct as having the intention to commit a crime, to as nuance as being negligent.
However, I wonder what if someone is a victim of blackmail and is forced to commit a crime. The victim knew the law, knew that his/her action is in conflict with the law, hence you can argue that they had the intention. Would a criminal case be applicable?