Section 154 of the CrPC does not provide for making any preliminary inquiry. However, as held in the case of Lalita Kumari v. Govt. of U.P (2014) 2 SCC 1, a preliminary inquiry is permissible if the information received does not disclose a cognizable offence and indicates the necessity for an inquiry. A preliminary inquiry must be conducted only to ascertain whether a cognizable offence is disclosed. However, sub-Section (3) of Section 173 of the BNSS makes a significant departure from Section 154 of the CrPC. It provides that when information relating to the commission of a cognizable offence which is made punishable for 3 years or more but less than 7 years is received by an officer-in-charge of a police station, with the prior permission of a superior officer as mentioned therein, the police officer is empowered to conduct a preliminary inquiry to ascertain whether there exists a prima facie case for proceeding in the matter. However, under Section 154 of the CrPC, as held in the case of Lalita Kumari v. Govt. of U.P (2014) 2 SCC 1, only a limited preliminary inquiry is permissible to ascertain whether the information received discloses a cognizable offence. Moreover, a preliminary inquiry can be made under the CrPC only if the information does not disclose the commission of a cognizable offence but indicates the necessity for an inquiry. Sub-Section (3) of Section 173 of the BNSS is an exception to sub-Section (1) of Section 173. In the category of cases covered by sub-Section (3), a police officer is empowered to make a preliminary inquiry to ascertain whether a prima facie case is made out for proceeding in the matter even if the information received discloses commission of any cognizable offence. That is very apparent as sub-Section (3) of Section 173 refers explicitly to receiving information relating to the commission of a cognizable offence. Therefore, in a case where sub-Section (3) of Section 173 is applicable, even if the information pertaining to the commission of any cognizable offence is received, an inquiry can be conducted to ascertain whether a prima facie case exists for proceeding in the matter. The intention appears to be to prevent the registration of FIRs in frivolous cases where punishment is up to 7 years, even if the information discloses the commission of the cognizable offence. However, under Section 154 of the CrPC, the inquiry permitted by paragraph 120.2 of the decision in the case of Lalita Kumari v. Govt. of U.P (2014) 2 SCC 1 is limited only to ascertain whether the cognizable offence is disclosed.
Under sub-Section (3) of Section 173 of the BNSS, after holding a preliminary inquiry, if the officer comes to a conclusion that a prima facie case exists to proceed, he should immediately register an FIR and proceed to investigate. But, if he is of the view that a prima facie case is not made out to proceed, he should immediately inform the first informant/complainant so that he can avail a remedy under sub-Section (4) of Section 173.