When a serious crime occurs – a murder, a robbery, a rape – the first institution society turns to is the police. But what exactly authorises a police officer to swing into action? Can they investigate on their own, or do they need a court’s permission every single time? Under India’s criminal procedure law, the answer depends critically on whether an offence is cognizable or not. The legal framework governing police investigation of cognizable offences – originally laid down in the Code of Criminal Procedure, 1973 (CrPC) and now carried forward under the Bharatiya Nagarik Suraksha Sanhita, 2023 (BNSS) – defines this authority in clear, precise terms. Understanding these provisions is essential for anyone studying criminal justice in India.
Table of Contents
- What is a cognizable offence?
- Section 156 CrPC: The police officer’s power to investigate
- Section 157 CrPC: The procedure for investigation
- Step 1: Send a report to the Magistrate – immediately
- Step 2: Proceed to the spot and investigate
- The rank requirement: Who can be deputed?
- When a private individual may be entrusted with investigation
- Exceptions to the duty to investigate
- The role of the Magistrate: Oversight, not control
- What has changed under the BNSS, 2023?
- The investigation process: A quick summary
What is a cognizable offence?
Section 2(c) of the CrPC defines a cognizable offence as one in which a police officer may arrest a person without a warrant. These are generally serious crimes – murder, rape, dacoity, dowry death – where immediate police action is considered necessary to protect society. The punishment for such offences typically involves imprisonment of three years or more. In contrast, non-cognizable offences like simple assault, defamation, or forgery are less serious and require the police to obtain a magistrate’s order before investigating.
One important rule to remember: when a case involves multiple offences, of which at least one is cognizable, the entire case is treated as a cognizable case. This means the police get full investigative authority over all the charges, even the non-cognizable ones.
Section 156 CrPC: The police officer’s power to investigate
Section 156 of the CrPC is the foundational provision. It confers on the officer in charge of a police station the power to investigate any cognizable case falling within the local jurisdiction of that station – and crucially, to do so without any order from a Magistrate. This is the defining feature of cognizable offences: the police can begin their investigation the moment they receive information about the commission of the crime.
The section also includes an important protective clause: no proceeding of a police officer in a cognizable case can be called into question at any stage on the ground that the officer was not empowered to investigate it. This prevents technical challenges from derailing a legitimate investigation after the fact.
Section 157 CrPC: The procedure for investigation
While Section 156 grants the power to investigate, Section 157 lays down the procedure that must be followed once the officer in charge has reason to suspect the commission of a cognizable offence. This section applies the moment the police have any grounds for suspicion – whether through a formal FIR or any other source of information.
Step 1: Send a report to the Magistrate – immediately
The very first obligation under Section 157(1) is to send a preliminary report (called an occurrence report) to a Magistrate empowered to take cognizance of the offence. The word used in the statute is “forthwith” – which courts have interpreted to mean within a reasonable time, without any undue or unexplained delay. The purpose of this report is not to seek the Magistrate’s permission (which is not needed) but to keep the Magistrate informed so that judicial oversight over the investigation can be maintained. As held in Pala Singh v. State of Punjab (AIR 1972), this provision is designed to ensure the Magistrate can control the investigation and give directions under Section 159 if required.
Failure to send this report promptly is treated seriously. The Patna High Court in Hafiz Mohammad v. Emperor observed that such failure opens the police to the suspicion of fabricating evidence. However, the Supreme Court in Ombir Singh v. State of U.P. (2011) has clarified that mere delay in sending the report does not by itself vitiate the trial or entitle an accused to acquittal, unless actual prejudice is shown.
Step 2: Proceed to the spot and investigate
After sending the report, the officer in charge must either proceed personally to the scene of the crime or depute a subordinate officer to do so. This on-the-spot investigation involves collecting evidence, examining witnesses, and taking measures for the discovery and arrest of the offender.
The rank requirement: Who can be deputed?
Not just any police officer can be assigned to investigate a cognizable offence. Section 157(1) explicitly states that the subordinate officer deputed must not be below the rank prescribed by the State Government through a general or special order. In most states, this rank has been set at Sub-Inspector (SI) or above. Head Constables, who are below this rank, are generally not empowered to conduct the investigation independently.
This question was directly addressed by the Rajasthan High Court, which examined a case where a Head Constable had conducted the investigation and filed a chargesheet. The court, after reading Section 157 alongside Rule 6.1 of the Rajasthan Police Rules, 1961, held that police officials below the rank of ASI (Assistant Sub-Inspector) are not empowered to independently investigate cognizable offences, and that no general or special order had been issued by the State Government in Rajasthan to authorise Head Constables to do so. The matter was referred to a larger bench given its significance.
The key principle is this: the State Government determines the minimum rank for deputation, and until a formal order extends this power to Head Constables, investigation is properly conducted only by officers of and above the rank of ASI or Sub-Inspector.
When a private individual may be entrusted with investigation
Section 2(h) of the CrPC defines “investigation” to include any proceeding conducted by a police officer or a person authorised by the Magistrate (other than the Magistrate herself) for the purposes of collecting evidence. This means a private individual – not a police officer – can be tasked with investigation, but only when specifically authorised by a Magistrate. This is not the norm; it is an exceptional circumstance.
The Magistrate’s power to order an investigation (including by a private person so authorised) flows from Section 156(3) CrPC, which allows a Magistrate empowered under Section 190 to direct an investigation. Courts have consistently held that such a direction does not amount to the Magistrate taking cognizance of the offence – it is a pre-cognizance mechanism to compel a proper investigation when the police have refused to act or have investigated inadequately.
Exceptions to the duty to investigate
Section 157 does not impose an absolute, unconditional duty to proceed to the spot in every case. Two important provisos carve out exceptions:
Proviso (a): When information about the offence is given against a named person and the case is not of a serious nature, the officer in charge need not personally proceed to the spot or depute a subordinate to investigate there.
Proviso (b): If it appears to the officer that there is no sufficient ground for entering on an investigation, he is not bound to investigate. However, in this case, he must record his reasons and inform the complainant accordingly. The Magistrate can then step in under Section 159 to direct an investigation if he disagrees with the police’s decision not to investigate.
The role of the Magistrate: Oversight, not control
A common misconception is that the Magistrate controls the police investigation. That is not accurate. Once an investigation has commenced, the Magistrate cannot stop it. The occurrence report sent under Section 157 is essentially a notification – it enables judicial oversight and allows the Magistrate to give directions under Section 159 if necessary, but it does not make the police subordinate to the Magistrate during the investigation.
The Supreme Court, in Sakiri Vasu v. State of U.P., affirmed that if a person is dissatisfied with the investigation even after an FIR has been registered, they can approach the Magistrate under Section 156(3) for appropriate directions. The Magistrate’s power in such situations is wide – but must be exercised with judicial application of mind, not mechanically. As the Supreme Court held in XYZ v. State of Madhya Pradesh (2022), while the word “may” in Section 156(3) gives the Magistrate discretion, that discretion must be exercised judiciously – especially in cases of serious offences like sexual assault, where a police investigation is almost always warranted.
What has changed under the BNSS, 2023?
From July 2024, the CrPC has been replaced by the Bharatiya Nagarik Suraksha Sanhita, 2023 (BNSS). The core principles remain the same, but important procedural upgrades have been introduced. Section 173 BNSS (replacing Section 154 CrPC) now allows an FIR to be lodged via electronic communication. Section 175 BNSS (replacing Section 156 CrPC) retains police autonomy to investigate cognizable offences without a magistrate’s order, while also introducing a new requirement: a preliminary inquiry (with the permission of a Deputy Superintendent of Police) for offences punishable with imprisonment between three and seven years, to check whether a prima facie case exists before formally registering the FIR.
Section 176 BNSS (replacing Section 157 CrPC) introduces modern evidence collection tools – mandatory forensic visits to crime scenes for offences punishable with seven or more years, and the option to record a rape victim’s statement via audio-video devices. These reforms are aimed at improving the evidentiary quality of investigations and reducing scope for tampering.
The investigation process: A quick summary
To bring all of this together, here is how the investigation of a cognizable offence proceeds in practice. The moment information of a cognizable offence is received – orally, in writing, or electronically – the officer in charge of the police station must record it as an FIR. The officer then has reason to suspect the commission of the offence, which triggers the duty under Section 157 (or Section 176 BNSS). An occurrence report is sent to the Magistrate. The officer – or a deputed subordinate of sufficient rank – goes to the crime scene, collects evidence, examines witnesses, and if necessary, arrests the offender. At the end of the investigation, a final report (chargesheet) is submitted to the Magistrate under Section 173 CrPC (Section 193 BNSS), who then decides whether to take cognizance and proceed to trial.
What do you think? Given that the minimum rank for deputing a subordinate officer varies by state government order, does this create an uneven standard of investigation quality across different states in India? And with the BNSS now requiring mandatory forensic visits for serious offences, will ground-level infrastructure in smaller towns and rural areas be adequate to meet this new obligation?
References
- https://indiankanoon.org/doc/1569253/
- https://bprd.nic.in/uploads/pdf/Comparison%20summary%20BNSS%20to%20CrPC.pdf
- https://blog.ipleaders.in/procedure-of-investigation-under-crpc/
- https://devgan.in/crpc/chapter_12.php
- https://drishtijudiciary.com/to-the-point/bharatiya-nagarik-suraksha-sanhita-&-code-of-criminal-procedure/section-157-of-crpc
- http://student.manupatra.com/Academic/Abk/Code-of-Criminal-Procedure/Chapter3.htm
- https://indiankanoon.org/doc/279174/
- https://www.livelaw.in/high-court/rajasthan-high-court/rajasthan-high-court-larger-bench-cognizable-offence-investigation-police-officer-below-asi-rank-section-157-crpc-252899
- https://blog.ipleaders.in/section-156-crpc/
- https://www.drishtijudiciary.com/to-the-point/ttp-code-of-criminal-procedure/procedure-of-investigation-under-crpc
- https://www.scconline.com/blog/post/2026/01/06/magistrate-ordered-investigation-section-175-3-bnss-analysis/
- https://legalonus.com/section-173-to-section-196-of-bnss-2023-investigation-process-under-the-bnss/
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