Dear applicant although Forensic Science course is a combination of law and science together. Forensic science can be learnt from the undergraduate level. The undergraduate programme is for three years, after which the student is provided with a B.Sc. degree. But yes there is chance of studying BA in Psychology as well but to be a forensic psychologist you need to have Science stream in 10+2 as a forensic psychologist is trained in psychology. They assist governments, judiciary and other investigative agencies. So you need B.Sc degree for that, but after your Arts degree you can become a genuine Psychologist.

Good luck!!!!