Having earned my degree in Criminal Justice, there is a possibility of becoming a forensic scientist, but it would be best if your taking it as a minor with your actual degree. Since forensic science studies is mostly science based courses, it would be best to take it on as you primary or major degree, especially if your genuinely interested in science. Criminal Justice is a Social Science degree, it's not primary focused on the scientific aspects of the course.
To make a significant choice in what you want to do, check various colleges and universities to inquire about their forensic science and criminal justice programs, speak with an advisor about your interests and make a genuine decision as to what you want to do and what career industry your trying to get into.
Examples of courses in a forensic science degree curriculum include:
- Introduction to Forensic Science
- General Chemistry
- Organic Chemistry
- Forensic Pathology
- Forensic Trace Evidence
- Physical Evidence
- Forensic Toxicology
- Crime Scene Processing
- Forensic Science Laboratory Internship
Required courses for a criminology major including:
- Introduction to criminology
- Introduction to criminal justice
- Law and economics
- Labor economics
- Philosophy of law
- Classical sociological theory
- Gangs and organized crime
- American constitutional law
- Cognitive neuroscience
- Statistics for the social sciences
Sherman, Fraser. "What Major Should Someone Who Wants to Be a Criminologist Choose?" Work - Chron.com, http://work.chron.com/major-should-someone-wants-criminologist-choose-16880.html. 19 February 2019.
I hope this will assist you with your career options.
Forensic science is a very chemistry heavy career path. You could take a minor in criminal justice, as this would relate to the field. However, the classes necessary for a criminal justice major will not satisfy those needed for forensic science.