Forensic Science is one of the specialisations in LLM to become a criminal lawyer. To start off your journey after your 12th, you should appear for any of the Law Entrance Examinations like CLAT, LSAT, AP LAWCET, TS LAWCET, AILET, etc. Post LLB, you need to appear for Law entrance exams like CLAT PG, etc and then take up LLM. And you have to select Forensic Science as one of your subjects. Or you can also study 1 year Diploma courses in Criminal Law.