Law Enforcement

When a police officer is accused of wrongdoing, who investigates?

There is no single answer, and the differences matter. This guide sets out the arrangements that recur — internal units, external statutory bodies, prosecutors, and bodies that investigate and prosecute at once — and the systems that use none of them.

Fact-checkedSafety review clearedLast updated 10 August 2026Last reviewed 10 August 2026

In short

When a police officer is accused of wrongdoing, the investigation may be conducted by the officer’s own service, by a different police service, by a dedicated external body, by a prosecutor, or by a body that investigates and prosecutes at once. Which of these applies is set nationally, and the answer changes what the process can produce.

Why it exists

The difficulty is structural rather than moral. An organisation investigating its own members has an interest in the result, and the people conducting the investigation share an employer, a culture and often a workplace with the person under investigation. None of that requires bad faith to be a problem: it is enough that the findings are hard for an outsider to rely on.

AnalysisEvery arrangement below is an attempt to introduce distance. They differ in how much distance, at what cost, and for which categories of allegation.

How it works

United Nations guidance treats internal control as the first degree of control in any police accountability system, operating preventively as well as reactively. It is the layer everything else is built on top of, not an alternative to external scrutiny.

The service investigates itself: An internal unit conducts the investigation. Fastest access to records and personnel, and the arrangement with the least distance from the subject.
Another police service investigates: A neighbouring or national force is asked to investigate. More distance than an internal unit, and still an investigation by police of police.
An external statutory body investigates: A body outside the police, created by statute, investigates defined categories of matter. The remit is usually narrower than the name suggests — South Africa’s Directorate is confined to deaths, firearm discharges and allegations of torture, assault or corruption.
An external body investigates and prosecutes: The strongest form of separation. Norway’s Bureau is a national investigation and prosecution agency for offences by police and prosecuting-authority employees.
A prosecutor or investigating judge directs: Where prosecutors lead investigations generally, they lead these too, and the separation comes from the ordinary criminal process rather than from a dedicated body.

The categories are not mutually exclusive. Czechia’s General Inspection of Security Forces investigates suspected crimes by officers of the police, the prison service and the customs administration and opens their criminal prosecutions — an external investigator whose remit extends beyond policing.

Common misconceptions

Widely held beliefs that do not match how the system actually operates.

Common belief: Every country has an independent body that investigates the police.
In practice: Many do not. Nigeria has constitutional police oversight through the Police Service Commission and the Nigeria Police Council, and no separate independent police-complaints board.
Common belief: An external body investigates every complaint against the police.
In practice: Most are confined by statute to defined categories — commonly deaths, serious injury and alleged criminality — and everyday conduct complaints return to the police service.
Common belief: Investigating is the same as being able to act on the result.
In practice: Investigation, discipline and prosecution are separate powers held by different bodies in most systems. A body may establish what happened and have no authority to do anything about it beyond reporting.
Common belief: An independent investigator means the process is effective.
In practice: The existence of a body is a fact about institutional design. Whether it works is a separate, empirical question that depends on powers, resourcing and access, and this platform does not infer one from the other.

How this varies between jurisdictions

A required section on every guide. Arrangements differ between countries, and we say how.

Whether a dedicated external body exists at all is the first and largest difference.
Where one exists, its remit may be a short statutory list rather than all police conduct.
Whether it can compel evidence and testimony, and from whom, differs and is rarely apparent from the body’s name.
Whether it prosecutes, refers to a prosecutor, or only reports is a fundamental difference in what an investigation can lead to.
Some bodies cover several security services rather than police alone.

New Zealand illustrates the separation of watching from prosecuting: the Independent Police Conduct Authority was established by Parliament in 1989, states that it is not part of the New Zealand Police, and receives and investigates complaints.

Worked examples

Systems this platform has researched. Each example links to the dossier it draws on.

Norway: Norway places both functions in one external body: the Bureau for the Investigation of Police Affairs is a national investigation and prosecution agency for offences by police and prosecuting-authority employees, sitting outside the ordinary police and prosecution chain.
South Africa: South Africa uses an external statutory investigator with a bounded remit — the Independent Police Investigative Directorate, created by Act 1 of 2011, for deaths in custody or resulting from police action, discharge of official firearms, and allegations of torture, assault or corruption.
Czechia: Czechia’s General Inspection of Security Forces investigates suspected crimes by officers of the Police, the Prison Service and the Customs Administration and opens their criminal prosecutions — an external investigator whose remit is wider than policing.
New Zealand: New Zealand separates the watching from the prosecuting: the Independent Police Conduct Authority, established by Parliament in 1989, is not part of the New Zealand Police and receives and investigates complaints, while criminal decisions rest elsewhere.
France: France shows two of these categories operating at once, which is why they are not mutually exclusive. Each national force has its own inspection générale, and each is inside the force it examines — the IGPN is by décret “un service actif de la direction générale de la police nationale”. Those internal bodies also act as judicial police: the IGPN conducts criminal investigations “d’initiative ou sur instruction de l’autorité judiciaire”, and the gendarmerie’s inspection conducts those entrusted to it and informs the judicial authority where the failings found may amount to an offence. So the service investigates itself and a prosecutor directs, in the same arrangement.

Where the pattern does not hold

Systems at the same level that arrange this differently. The pattern above is a pattern, not a rule.

Nigeria: Nigeria has constitutional police oversight and no body of this kind: the Police Service Commission appoints, promotes and disciplines officers other than the Inspector-General, and the Nigeria Police Council handles policy and general supervision, with no separate independent police-complaints board. A country can take oversight seriously in its constitution and still have no external investigator.

Rights and accountability

For a person making a complaint, the practical questions are narrow: which body receives it, whether that body can investigate this category of matter, and what it is able to do with a finding. The three have different answers in most systems, and the third is the one most often assumed.

Where a matter is criminal, it normally enters the ordinary criminal process regardless of which body investigated, which is why the relationship between the investigating body and the prosecution service is worth establishing in any specific system.

What we could not establish

This guide describes arrangements that recur across the systems this platform has researched. It does not establish who investigates police in any country not named here, and it makes no claim that any arrangement produces better outcomes than another.

Where to go next

Which bodies can examine what the police did, and what can each of them actually do?
Internal investigation, independent complaints bodies, inspectorates, prosecutors and courts examine police conduct in different ways and with different powers. This guide explains what each mechanism is for and why the differences between them matter to anyone trying to use one.
Why does police accountability matter, and what is it actually for?
Accountability is usually framed as a response to misconduct. This guide explains the structural argument: enforcement bodies hold discretionary powers that cannot be fully specified in advance, and accountability is the mechanism that makes discretion answerable.
When police agencies work together, is one of them in charge?
Cooperation between agencies is routinely mistaken for hierarchy. This guide separates command from coordination, and explains why a national body can set standards for forces it cannot give orders to.

Where this connects

Institutions: Police complaints body, Ombuds and rights institutions, Prosecution service.

Sources

E4J University Module Series — Crime Prevention and Criminal Justice, Module 5 (Police Accountability, Integrity and Oversight), Topic 2: Key mechanisms and actors in police accountability and oversight
United Nations Office on Drugs and Crime (Education for Justice) · International organisation · link verified 2026-08-10
The UNODC teaching module on police accountability mechanisms, read directly. Supports UNODC's own conceptual framework of accountability 'before, during and after the act' (ex-ante, ongoing and ex-post oversight); that internal control within the police service is the first degree of control in any police accountability system and works both preventively and reactively; that legal provisions alone are often insufficient for the day-to-day exercise of police powers, so services need comprehensive professional standards and codes of conduct giving practical guidance — the module's own worked example is guidance on arrest and detention procedures; and that because officers hold wide discretion and meet ethical dilemmas (the module instances bending laws for perceived greater law-enforcement objectives, and deceptive interrogation tactics used to extract a confession) services also need a code of ethics built on impartiality, fairness, equality, justice and honesty. Describes how accountability systems are DESIGNED. It does not establish that any particular system works, and no effectiveness or public-trust claim on this platform rests on it.
The Norwegian Bureau for the Investigation of Police Affairs
Spesialenheten for politisaker (Norway) · Government publication · link verified 2026-07-26
The Bureau's own English site, read directly. Supports that it is "a national investigation and prosecution agency" whose purpose "is to investigate cases where employees of the police or prosecuting authority are suspected of committing criminal offences in the course of duty" — an independent police-crime body outside the ordinary police and prosecution chain.
Independent Police Investigative Directorate Act 1 of 2011 (South Africa)
Government of South Africa (gov.za) · Legislation · 2011 · link verified 2026-07-27
The Independent Police Investigative Directorate Act 1 of 2011 (commenced 1 April 2012), from gov.za. Supports the establishment of the Independent Police Investigative Directorate (IPID) as the independent body that investigates certain serious matters involving the police — deaths in custody or as a result of police action, the discharge of official firearms, and allegations of torture, assault or corruption by police officers. Establishes the external police-complaints/investigation body.
General Inspection of Security Forces (Generální inspekce bezpečnostních sborů, GIBS)
Generální inspekce bezpečnostních sborů (Czech Republic) · Government publication · link verified 2026-07-26
The GIBS official site, read directly. Supports that the General Inspection of Security Forces is an independent body that searches for, detects and investigates suspected crimes by officers of the Police of the Czech Republic, the Prison Service and the Customs Administration, and opens their criminal prosecutions. Its statutory basis is Act No. 341/2011 Coll. on the General Inspection of Security Forces (the act number independently corroborated in the verification pass).
Independent Police Conduct Authority (New Zealand) — about us
Independent Police Conduct Authority (New Zealand) · Government publication · link verified 2026-07-27
The IPCA's own site, read directly. Supports that the Independent Police Conduct Authority is "an independent body set up by Parliament to keep watch over the Police", that "we are not part of the NZ Police" and "under law we are fully independent", that it was established in 1989, and that it receives and investigates complaints against the Police. Establishes the external police-complaints body.
Constitution of the Federal Republic of Nigeria, 1999 (as amended)
National Human Rights Commission of Nigeria (official text host) · Legislation · 1999 · link verified 2026-07-27
The Constitution of the Federal Republic of Nigeria 1999 (as amended, the copy carrying amendments through 2011), downloaded as the full official PDF (775,326 bytes, 137 pages) and confirmed verbatim in two independent passes. Supports: s 4 and the Second Schedule (the division of legislative power — the Exclusive Legislative List for the Federation, the Concurrent List for both, and residual matters for the States under s 4(7)); Exclusive List item 45 and s 214(1) ("There shall be a police force for Nigeria … no other police force shall be established for the Federation or any part thereof" — a single national police); Exclusive List item 48 ("Prisons" — federal corrections); s 6(5) (the superior courts of record — the federal Supreme Court, Court of Appeal, Federal High Court and FCT High Court, and the State High Courts, Sharia Courts of Appeal and Customary Courts of Appeal); s 230/233/235 (the Supreme Court as apex, its decisions final); s 237 (the Court of Appeal); s 275/280 (State Sharia and Customary Courts of Appeal, headed by a Grand Kadi); s 150/174 (the Attorney-General of the Federation, a Minister and Chief Law Officer, with power to institute, take over or discontinue federal prosecutions) and s 195/211 (each State Attorney-General with the mirror power for state offences); s 215 (the Inspector-General commanding the Nigeria Police Force, with the President's lawful-directions power); s 153 and the Third Schedule (the National Judicial Council, the Police Service Commission and the Nigeria Police Council); and s 81(3)/292 (judicial funding through the NJC and security of tenure). Establishes that Nigeria is a federation in which police and prisons are federal, while courts, prosecution and (residually) criminal law operate at both the federal and state levels.
Décret n° 2013-784 du 28 août 2013 relatif aux missions et à l'organisation de l'inspection générale de la police nationale
République française (Légifrance) · Legislation · 2013-08-28 · link verified 2026-08-10
The founding instrument of the IGPN. Supports the exact wording of article 1, 'L'inspection générale de la police nationale est un service actif de la direction générale de la police nationale' (version in force from 1 July 2023, as modified by décret n° 2023-530 of 29 June 2023); that its scope covers the services of the DGPN, the préfecture de police and, under conditions, the DGSI; article 3, 'une mission générale d'inspection, d'étude, d'audit et de conseil' together with internal control and risk management by delegation; article 4, 'L'inspection générale de la police nationale diligente des enquêtes judiciaires, d'initiative ou sur instruction de l'autorité judiciaire' and 'Elle reçoit les plaintes et dénonciations'; and article 5 (in force from 17 July 2025, as modified by décret n° 2025-651 of 16 July 2025), under which administrative investigations are conducted on the instruction of the Minister of the Interior, the DGPN, the DGSI or the préfet de police, with an urgency exception. It does NOT support any claim about how many investigations are conducted, about their outcomes, about the effectiveness or independence of the IGPN, or about any deontology mandate, which this text does not confer in terms.
Arrêté du 23 avril 2025 relatif aux attributions et à l'organisation de l'inspection générale de la gendarmerie nationale
République française (Légifrance) · Legislation · 2025-04-23 · link verified 2026-08-10
The current attributions of the IGGN, and the reason any description resting on the previous text is out of date: article 4 abrogates the arrêté of 15 January 2019. Supports that the IGGN carries out inspection, audit, study, investigation, evaluation and expertise missions covering the employment of resources, human resources, administration, logistics and finance, security of installations and information systems, protection of personal data, the health and safety of personnel and preservation of the environment; that it is 'chargée du respect des règles de déontologie' and makes the recommendations those rules require; that it 'diligente, sur instruction ou d'initiative, les enquêtes administratives se rapportant au non-respect de ces règles'; that it 'informe l'autorité judiciaire lorsque les manquements constatés sont susceptibles de constituer une infraction pénale'; that it 'diligente les enquêtes judiciaires qui lui sont confiées et satisfait aux réquisitions judiciaires'; that it 'assure le recueil et le traitement des doléances que lui adressent les particuliers' and collects reports from gendarmerie personnel who are victims or witnesses of harassment, discrimination or violence within the institution; and that the observatoire de la gendarmerie pour l'égalité et contre les discriminations is attached to it. It does NOT support any claim about outcomes, volumes or effectiveness.