There is no definitive background that a forensic artist comes from. Full-time forensic art positions are extremely rare. There are but a handful of full-time artist in the United States. The pay scale of a forensic artist depends on factors, such as geographic location, the size of the employing department, and your ability to market yourself. The most important necessity to becoming a successful forensic artist is passion for the work and a desire to become the best you can be with a strong desire to learn and succeed.
Some instructors agree that at times the results are better with students with no previous training.
You do not HAVE to take all the courses offered to be a successful artist and you DO NOT need to possess a four year degree. You DO however need training in a specific aspect of forensic art. If your desire is strictly in composite sketching, then concentrate your efforts to receiving the training in composite art. If your talents and desires rest on the facial reconstruction aspect of forensic art, then take the facial reconstruction courses. BUT, if you get the chance to take all the courses, by all means do so.