Investigation is the process by which the police collect evidence relating to the commission of a cognizable offence, including proceeding to the spot, ascertaining facts, discovering and arresting the accused, and collecting evidence. Under Indian law, investigation is defined in Section 2(h) of the Code of Criminal Procedure, 1973 (now Section 2(1)(i) of the BNSS, 2023).
Legal definition
Section 2(h) of the Code of Criminal Procedure, 1973 provides:
Section 2(h): "Investigation" includes all the proceedings under this Code for the collection of evidence conducted by a police officer or by any person (other than a Magistrate) who is authorised by a Magistrate in this behalf.
Investigation is distinct from "inquiry" (which is a judicial proceeding conducted by a Magistrate) and "trial" (which is a judicial adjudication of guilt or innocence). Investigation is an executive function conducted primarily by the police.
New law equivalent: Under the BNSS, 2023, Section 2(1)(i) provides the same definition. Significant reforms include mandatory forensic investigation for offences punishable with seven years or more (Section 176 BNSS), mandatory videography of crime scenes, and a requirement to inform the victim of investigation progress within ninety days.
How courts have interpreted this term
H.N. Rishbud v. State of Delhi [AIR 1955 SC 196]
The Supreme Court identified the key steps that constitute investigation: (1) proceeding to the spot, (2) ascertaining the facts and circumstances of the case, (3) discovery and arrest of the suspected offender, (4) collection of evidence relating to the commission of the offence (examination of persons, search of places, seizure of articles), and (5) formation of an opinion as to whether there is a case to place before a Magistrate (filing of chargesheet or closure report).
Lalita Kumari v. Government of U.P. [(2014) 2 SCC 1]
A Constitution Bench of the Supreme Court held that registration of an FIR is mandatory under Section 154 CrPC when information discloses a cognizable offence, and the police have no discretion to conduct a preliminary inquiry before registering the FIR in such cases. However, a preliminary inquiry may be conducted in cases where the information does not clearly disclose a cognizable offence.
CBI v. Tapan Kumar Singh [(2003) 6 SCC 175]
The Supreme Court held that investigation is the exclusive domain of the investigating agency. Neither the Magistrate nor the court can direct the investigating officer on how to conduct the investigation, what evidence to collect, or what conclusions to draw. The court's role is limited to monitoring the progress and ensuring fairness.
Why this matters
Investigation is the foundation upon which the entire criminal prosecution rests. The quality of investigation determines whether the prosecution can successfully prove its case at trial. A flawed investigation — whether due to delay, incompetence, or mala fides — can result in acquittal even when the accused is guilty.
For practitioners, understanding the procedural timelines is critical. Under Section 167 CrPC (Section 187 BNSS), if the investigation is not completed within sixty days (for offences punishable with death, life imprisonment, or imprisonment for ten years or more) or ninety days (for other offences), the accused acquires an indefeasible right to default bail. This timeline acts as a powerful check on prolonged investigation.
The BNSS reforms introduce significant modernisation of the investigation process. Mandatory forensic investigation, videography of search and seizure, and electronic communication of investigation progress represent a shift towards transparency and scientific investigation. These reforms are intended to strengthen the evidentiary foundation of criminal cases and reduce the scope for allegations of evidence tampering.
Related terms
Related procedures:
Related concepts:
Frequently asked questions
What is the difference between investigation and inquiry?
Investigation is an executive function conducted by the police to collect evidence. Inquiry is a judicial proceeding conducted by a Magistrate to determine whether there is sufficient ground for proceeding with a trial. Investigation precedes the chargesheet; inquiry follows the complaint and precedes the trial.
Can a Magistrate order investigation?
Yes. Under Section 156(3) CrPC (Section 175(3) BNSS), a Magistrate empowered under Section 190 may order the police to investigate a cognizable offence. This power is frequently invoked when the police refuse to register an FIR or fail to investigate a case properly.
What happens if the police do not complete investigation within the prescribed time?
If investigation is not completed within sixty or ninety days (depending on the offence), the accused is entitled to default bail under Section 167(2) CrPC (Section 187 BNSS). This right is indefeasible and cannot be defeated by subsequent filing of the chargesheet.
Can a private person conduct investigation?
Generally, no. Investigation is a police function. However, under Section 2(h) CrPC, a person other than a Magistrate who is authorised by a Magistrate may conduct investigation. Additionally, agencies like the CBI, NIA, and ED conduct investigations under their respective special statutes.
This entry is part of the Veritect Indian Legal Glossary, a comprehensive reference of Indian legal terminology grounded in statutory text and judicial interpretation.
Last updated: 2026-03-27. Veritect provides this content for informational purposes and does not constitute legal advice.