First Information Report, in short, is called FIR. Under the provision of Section 154 Cr.P.C., any Complainant approaches the Police to register his Complaint and the Police upon receipt of the Complaint, it is duty bound to document the same in the Diary kept in their Station for such purpose.

[However, now that every Police Station is linked-up with the intranet facility and the Police upon receipt of the Complaint, document the Complaint and then issue a proof for receipt of the Complaint in the form of CSR.]

Then the Investigating Officer [IO] conducts an inquiry, prima facie, if the IO founds, was there any commission of offence, he then registers an FIR.

The FIR contains details as follows;

FIR number and year, date and time of FIR registered, Indian Penal provisions and or any Special Statute [applies on some cases] under which the offences are made out, name and contact details of the Complainant and Accused, place of occurrence, reproduction of entire Complaint given in written by the Complainant documented on the specified column in the FIR with seal and sign of the IO.

Otherwise, the CSR is a precursor for conducting an investigation, whereas an FIR is pre cursor to set in motion the Criminal Complaint against the Accused before the Court of Law for the remedy – Justice.  It is pertinent to mention here that the entire Cr.P.C. statute does not carry a word FIR or First Information Report directly, but only made categorical statement of it.   

Also read: DECODING SECTION 154 OF CR.P.C.