Forensic science (Forensics) is the application of a broad spectrum of sciences to answer questions of interest to the legal system. This may be in relation to a crime or to a civil action.
Like Forensic Science, Forensic psychology is structured around the law too. However, in forensic psychology there is an interaction of the practice or study of psychology AND the law. Psychologists in this line of work may work in prisons, jails, rehabilitation centers, police departments, law firms, schools, government agencies, in private practice, etc. Trying to think of one in real life? Think of Dr. Wong from Law & Order: SVU!