Police officer in the context of "Patrol car"

An aide-de-camp (English: /ˌeɪd dɪ ˈkæmp/ /-ˈkɒmp/; French: [ɛd də kɑ̃]; plural: aides-de-camp) is a personal assistant or secretary to a person of high rank, usually a senior military, police or government officer, or to a member of a royal family or a head of state. The term comes from a French expression meaning "helper in the military camp".

An aide-de-camp may participate at ceremonial functions, and the first aide-de-camp is typically the foremost personal aide. This is not to be confused with an adjutant, who is the senior administrator of a military unit.

A police station is a facility operated by police or a similar law enforcement agency that serves to accommodate police officers and other law enforcement personnel. The role served by a police station varies by agency, type, and jurisdiction, but in larger agencies there may be multiple police stations that serve as regional or area sub-headquarters for personnel assigned to certain beats, administrative divisions, or police units, while in smaller agencies there may be fewer stations or even one singular police headquarters.

A citizen's arrest is an arrest made by a private citizen – a person who is not acting as a sworn law-enforcement official. In common law jurisdictions, the practice dates back to medieval England and the English common law, in which sheriffs encouraged ordinary citizens to help apprehend law breakers.

Police misconduct is inappropriate conduct and illegal actions taken by police officers in connection with their official duties. Types of misconduct include among others: sexual offences, coerced false confession, intimidation, false arrest, false imprisonment, falsification of evidence, spoliation of evidence, police perjury, witness tampering, police brutality, police corruption, racial profiling, unwarranted surveillance, unwarranted searches, and unwarranted seizure of property.

A search warrant is a court order that a magistrate or judge issues to authorize law enforcement officers to conduct a search of a person, location, or vehicle for evidence of a crime and to confiscate any evidence they find. In most countries, a search warrant cannot be issued in aid of civil process.

Jurisdictions that respect the rule of law and a right to privacy constrain police powers, and typically require search warrants or an equivalent procedure for searches police conducted in the course of a criminal investigation. The laws usually make an exception for hot pursuit: a police officer following a criminal who has fled the scene of a crime has the right to enter a property where the criminal has sought shelter. The necessity for a search warrant and its abilities vary from country to country. In certain authoritarian nations, police officers may be allowed to search individuals and property without having to obtain court permission or provide justification for their actions.

The Katyn massacre was a series of mass executions of Poles carried out by the Soviet Union between April and May 1940. Though the killings also occurred in the Kalinin and Kharkiv NKVD prisons and elsewhere, the massacre is named after the Katyn forest, where some of the mass graves were first discovered by Nazi German forces in 1943. Nearly 22,000 Polish military and police officers, border guards, and intelligentsia prisoners of war were executed by the NKVD (Soviet secret police), at Joseph Stalin's orders.

The massacre is qualified as a crime against humanity, crime against peace, war crime and (within the Polish Penal Code) a Communist crime. According to a 2009 resolution of the Polish parliament's Sejm, it bears the hallmarks of a genocide.

Discretion is the power or right to decide or act according to one's own judgment; freedom of judgment or choice. In a broader social context, it refers to the quality of being discreet, encompassing the ability to behave or speak in such a way as to avoid causing offense or revealing private information.

The concept is foundational in various fields, particularly in law, where it refers to the authority granted to an official (such as a judge or police officer) to make decisions based on their assessment of the specific circumstances rather than by strict adherence to a rigid code. It acts as a necessary counterbalance to the rigidity of written rules, allowing for equity and mercy in complex human situations.

The National Police Agency (Japanese: 警察庁, Hepburn: Keisatsu-chō) is the central coordinating law enforcement agency of the Japanese police system. Unlike national police in other countries, the NPA does not have any operational units of its own aside from the Imperial Guard; rather, it is responsible for supervising Japan's 47 prefectural police departments and determining their general standards and policies, though it can command police agencies under it in national emergencies or large-scale disasters. It is under the National Public Safety Commission of the Cabinet Office.

As of 2017, the NPA has a strength of approximately 7,800 personnel: 2,100 sworn officers, 900 guards, and 4,800 civilian staff.

A constable is a person holding a particular office, most commonly in law enforcement. The office of constable can vary significantly in different jurisdictions. Constable is commonly the rank of an officer within a police service. Other people may be granted powers of a constable without holding this title.

A first responder is a person with specialized training who is among the first to arrive and provide assistance or incident resolution at the scene of an emergency. First responders typically include:

• law enforcement officers (commonly known as police officers),
• emergency medical services members (such as EMTs or paramedics), and
• fire service members (such as firefighters, search and rescue members, technical/heavy rescue members, etc.)

In some jurisdictions, emergency department personnel, such as doctors and nurses, are also required to respond to disasters and critical situations, designating them first responders; in other jurisdictions, military and security forces may also be authorized to act as first responders.