From Justice Definitions Project

What is investigation

An investigation[1] means an inquiry to search, examine, and ascertain facts. In criminal law, the investigation serves as the central component of the case. A thorough investigation is necessary to provide a fair trial for the accused.

Official definition of investigation

As per Section 2(h) of The Criminal Procedure Code, 1973 (CrPC) or Section 2(j) of The Bhartiya Nagrik Suraksha Sanhita, 2023 (BNSS), an “investigation” entails the collection of evidence conducted by a police officer or by any person (other than a Magistrate) who is authorized by a Magistrate on this behalf.

In the course of a criminal investigation[2], the police may carry out a search, arrest a suspect, ask for an investigation into matters outside of their jurisdiction, perform a medical examination, carry out an identity verification procedure, demand production, record confessions and statements, and more. The CrPC governs every facet of the inquiry, and also establishes safeguards against the authorities using their authority arbitrarily.

Investigation, especially in order to investigate sex crimes, has also been defined as under the Standard Operating Procedure (SOP). It states that in order to investigate sex crimes, a need was felt to improve the quality of investigation and to secure conviction. So, as far as possible, investigation of crime against women shall be conducted by a woman officer. An investigative team including three to four experienced police officers, one of whom should be appointed as the Chief Investigating Officer, should be assembled whenever necessary. The team should include at least one woman officer. Since sexual assault is a serious crime, cases involving it should, in most cases, be looked into by a senior and experienced police officer. The SOP does not specify a deadline, however it must be completed as soon as possible.

Procedure and stages of Investigation

First Information Report (FIR)

First Information Report (FIR) is a written document[3] prepared by the police when they receive information about the commission of a cognizable offense, as per Section 154 of CrPC and Section 173 of BNSS.

The Order to Investigate by the Magistrate

A magistrate can order an investigation, if he is empowered under Section 190 of CrPC or Section 210 of BNSS. An investigation started under Section 156(3) CrPC and Section 175(3) of BNSS ends up only with the report filed by the police as indicated in Section 173. As laid down by C.B.I. v. Shiv Kumar Singh (1998)[4], the Magistrate can also direct the Central Bureau of Investigation (CBI) to investigate the cognizable offense if the statutory investigating agency has not worked effectively or is not discharging its function fairly and impartially. Hence, the investigation of a cognizable offense, can be carried out either by the will of the officer in charge or by the Magistrate’s order. The investigation under Section 156(3) CrPC can be commenced by the police even without the order of a Magistrate when a Magistrate orders investigation under Chapter XII he does so before he takes cognizance of the offense.

Investigation under Section 202 CrPC

Investigation under S. 202 is limited in nature. Limited investigation under Section 202 CrPC is after taking cognizance only for helping the Magistrate to decide whether or not there is sufficient ground for him to proceed further. Herein, magistrates have the authority to postpone issuing legal proceedings against an accused if they deem it necessary, particularly when the accused resides outside their jurisdiction. They can conduct inquiries themselves or direct investigations by police or other suitable individuals to determine if there's enough reason to proceed, with exceptions for cases exclusively triable by a higher court or complaints not meeting specific requirements.

Investigating Non-Cognizable cases

An investigating officer must first get an order from a magistrate in order to start an inquiry into non-cognizable offenses. The investigating officer's powers will be the same as an officer in the event of a cognizable offense after this permission is granted.

Gathering evidence

Section 157 of CrPC and Section 176 of BNSS provide the preliminary inquiry method[5]. According to these, after receiving the information about the crime, the officer in charge of the police station is empowered to investigate the case and to send the report of the same to the Magistrate, who would then take cognizance of the case. The police need to go to the crime scene to collect evidence and arrest the suspect if needed. They can also deny investigation and are not bound to investigate, and can inform the magistrate, on the following grounds:

  • that the case involves some non-cognizable offenses, which cannot be investigated without the order of the Magistrate.
  • That there exist no sufficient grounds to carry out the investigation.
  • That the information is given against a person’s name and is in regard to the commission of a non-serious nature.

Section 161 of CrPC or Section 180 of BNSS deals with the oral examination[6] of witnesses by the police. They are required to answer each and every question asked by the police during the interrogation. However, they are not bound to answer such questions wherein the answers have a tendency to expose him to a criminal charge, or to a penalty, or forfeiture.

Search & Seizure

Search and seizure under CrPC[7] are a crucial step in a proper investigation. The police have two ways to carry out a search and seizure. First, issue a legal warrant; and second, without a warrant. In Section 100 of the CrPC and Section 103 of BNSS, general guidelines for search and seizure are described. With a few minor exceptions, these guidelines are often observed in situations governed by the Indian Penal Code and other legislation. Therefore, the investigating police shall adhere to the guidelines in Sections 100 and 165 of the CrPC [and Section 185 of the BNSS] in all circumstances involving search and seizure. It's important to note that the police are required to follow certain precise protocols for search and seizure under certain special legislation, such as the Narcotic Drugs and Psychotropic Substances Act, 1985. It might be necessary for the police to search several locations. Some might be at the crime scene, while others might be in places where the perpetrators are hiding or where there is evidence.

Moreover, as per Section 92 CrPC and Section 95 of BNSS, the procedure regarding letters and telegrams involves a District Magistrate, Chief Judicial Magistrate, Court of Session, or High Court directing postal or telegraph authorities to deliver or detain documents, parcels, or items needed for investigations or legal proceedings under the law, depending on the authority's opinion and the nature of the request. Other magistrates, police commissioners, or district superintendents can also request searches and detentions pending orders from higher authorities for similar purposes.

Pre-trial detention

Pre-trial detention[8] is not a sanction, but a measure to safeguard a criminal procedure. They are legally presumed innocent until proven guilty but may be held in conditions that are worse than those for convicted prisoners and sometimes for years on end.


Chapter V of CrPC specifically deals with Arrest in both CrPC and BNSS. Arrest means the deprivation[9] of a person of his liberty by legal authority or by an apparent legal authority. Arrest can be made by a Police Officer under Section 41 of CrPC and Section 35 of BNSS. It states that any police officer may arrest without an order of Magistrate and without a warrant when any person Commits cognizable offense in his presence, commits cognizable offense punishable with less than or equal to 7 years of imprisonment with or without fine:

  • Against whom reasonable complaint is made
  • Credible information has been received
  • Reasonable suspicion exists, if certain thresholds are fulfilled.

Case diary

The statements of witnesses recorded throughout the course of investigation shall be placed in the police case diary in accordance with Section 1721(1A) & (2) of the CrPC and Section 192 of the BNSS.

Closure report/ Charge Sheet

As per Section 173 CrPC and Section 193 BNSS, as soon as the investigation is completed, the officer in charge of the police station shall forward the charge-sheet or the closure report to a Magistrate empowered to take cognizance of the offense on a police report.

Legal Provisions relating to investigation

Further Investigation

Section 173(8) of CrPC deals[10] with further investigation and supplementary reports.  It is now a well-established legal concept that notice must be given to the first informant whenever a final form is filed by an investigating officer using their authority under section 173(2) of the CrPC. The informant has the option to file a protest petition, which could be viewed as a complaint petition in certain circumstances. Based on this, the learned magistrate may grant cognizance based on the information the investigating agency has put on file, provided they have complied with all legal requirements. The Magistrate may also then direct further investigation. In the case of H.N. Rishbud v. State of Delhi[11], the court had held that it does not follow, however, that the invalidity of the investigation is to be completely ignored by the Court during trial. While not declining cognizance, the Court will have to take the necessary actions to cure the illegality and rectify the defect when the breach of such a mandatory provision is brought to its attention at an early enough stage. This may involve ordering further investigation, depending on the specifics of each case.

Re-investigation/ fresh investigation/ de-novo investigation

Re-investigation[12] entails a process of investigation de-novo, however, the CrPC is silent in relation to its process. Re-investigation without permission is prohibited, as it has the capability to wipe out the investigation done earlier. Normally, the High Court or Supreme Court as a principle, reserves the right for ordering “a fresh investigation”, when it is of the view that the investigation was flawed.

Transfer of Investigation

There is no cast iron formula for directing a transfer of investigation[13] to the CBI or another competent authority. The Court makes a decision after considering the facts and circumstances of the case, such as prima facie evidence of an offense, the gravity of the offense, and the impact of the offense on society.

Identification & Attendance of the Witnesses

Section 160 of the CrPC and Section 175 of the BNSS enshrine the authority to name and address the witnesses. A police officer has the right to summon anyone who seems to be familiar with the case's facts and circumstances to attend for questioning after looking into the crime and locating all relevant evidence, suspects, and witnesses.

Audio-Video Recordings during Investigation

The BNSS brought about significant changes regarding the use of audio-video recordings[14] during investigations. One notable provision is found in Section 185 of BNSS, which pertains to “Search by police officer”. It mandates that such searches be recorded using audio-video electronic means, preferably via a mobile phone. This requirement was absent in the corresponding Section 165 of the CrPC.

In Section 176, which deals with the “Procedure for investigation”, several sub-clauses introduce the use of audio-video recordings. Sub-clause (1) allows statements made before the police to be recorded through any audio-video electronic means, preferably a cell phone. This provision was missing in Section 157 of the CrPC. However, Section 161 regarding the “Examination of witnesses by police” does allow for recording statements by audio-video electronic means, a provision retained in the corresponding Section 180 of the BNSS.

Additionally, Section 154 of the BNSS mandates the videography of statements from victim-informants with physical or mental disabilities, a provision retained in Section 173. Furthermore, Section 176(3) introduces a mandatory requirement for videography during the process of collecting forensic evidence from crime scenes for offenses punishable with seven years or more. This provision, although subject to State government notification within five years, aims to enhance transparency and accountability in evidence gathering.

The inclusion of audio-video recordings in investigations represents a positive step toward ensuring transparency and accountability in police procedures. It aims to protect the rights of both accused individuals and victims while improving the quality of evidence presented in court. These inclusions align with the broader trend of leveraging technology in investigations, as seen in legislative and judicial developments. Moreover, the mandatory requirement for audio-video recordings during search and seizure proceedings addresses concerns regarding potential evidence manipulation and misuse of police power. Similarly, Section 176(3)’s requirement for videography during the collection of forensic evidence serves as a safeguard against irregularities and manipulation, further enhancing transparency and accountability in the criminal justice system.

Investigation in Summons case

In case an offence is triable as a summon case, if the investigation has not been concluded within six months of the date of arrest, the Magistrate has to make an order to stop all investigations related to the case. However, the Magistrate may not pass this order if the investigating officer satisfies the Magistrate that the continuation of the investigation is necessary for justice and some special reasons. The above-mentioned order of the Magistrate can be vacated by order of the Sessions Judge. The Sessions Judge can pass the order based on an application for further investigation and direct further investigation subject to directions on bail and other matters. In Hussainara Khatoon v. Home Secretary, State of Bihar[15], it was held that Section 167(5) of CrPC and Section 187 of BNSS is to be mandatorily complied with.

West Bengal has, however, made an addition to this criteria. Therefore, for the state of West Bengal, if:

  • there is a case triable as summon case and its investigation has not been concluded within six months,
  • Investigation of a case exclusively triable by Session Court is not completed within three years, or
  • Any other case’s investigation which has not been completed within two years from the date of the accused’s arrest or appearance

Then the Magistrate has to pass an order to stop the investigation and discharge the accused.

As Defined in Case Law

The Madras High Court has issued guidelines[16] to prevent harassment during police investigations in criminal complaints. In a recent case, the court emphasized the Investigating Officer's powers under Chapter XII of the CrPC but noted concerns about reported harassment incidents. The guidelines include serving written summons to individuals named in complaints, recording enquiry minutes, avoiding odd-hour summons, and following Lalita Kumari v. Govt. of U.P. (2014)[17] guidelines for preliminary inquiries or FIR registration. The Court made it clear that it would not usually interfere with police investigation under Section 482 of CrPC and Section 530 of BNSS, but it would not turn a blind eye to instances of harassment by the police under the guise of investigation.

Related concepts

Enquiry[18] is the second stage of a criminal case and it is done by the magistrate in court. Also, the aim here is not to gain extra information, but to determine whether certain claims are true or false.

Inquiry, under Section 116 of CrPC and Section 135 of BNSS, means that the Magistrate shall proceed to inquire into the truth of the information upon which action has been taken, and to take such further evidence as may appear necessary. An inquiry is defined under Section 2(g) of CrPC and Section 2(i) of BNSS as every inquiry, other than a trial, is conducted by a Magistrate or Court.


Cookies help us deliver our services. By using our services, you agree to our use of cookies.