Dear,

You have to clear a civil services examination which is conducted by UPSC.
Besides this, you can also get a post through SSC entrance exam and the basis of the CGL exam, you will become one of the officers in CID Department. The minimum qualification is required to apply for CID is that you need to pass the 12th exam.  To join CID, you must have done graduation in any stream from a recognized university.A candidate who has already completed graduation can join this department as a sub-inspector. There are many universities in India that offer degrees in criminology and criminal justice at the graduation level which may be helpful to join CID.With the help of UPSC, SSC & CGL exams which take place under the government of India, you can achieve your dreams soon.

Hope this helps!