Law enforcement agencyA law enforcement agency (LEA) is any government agency responsible for the enforcement of the law. LEAs which have their ability to apply their powers restricted in some way are said to operate within a jurisdiction. LEAs will have some form of geographic restriction on their ability to apply their powers. The LEA might be able to apply its powers within a country, for example the United States' Bureau of Alcohol, Tobacco, Firearms and Explosives or its Drug Enforcement Administration; within a division of a country, for example the Australian state Queensland Police; or across a collection of countries, for example international organizations such as Interpol, or the European Union's Europol.
Private investigatorA private investigator (often abbreviated to PI and informally called a private eye), a private detective, or inquiry agent is a person who can be hired by individuals or groups to undertake investigatory law services. Private investigators often work for attorneys in civil and criminal cases. In 1833, Eugène François Vidocq, a French soldier, criminal, and privateer, founded the first known private detective agency, "Le Bureau des Renseignements Universels pour le commerce et l'Industrie" ("The Office of Universal Information For Commerce and Industry") and hired ex-convicts.
ConstableA constable is a person holding a particular office, most commonly in criminal law enforcement. The office of constable can vary significantly in different jurisdictions. A constable is commonly the rank of an officer within the police. Other people may be granted powers of a constable without holding this title. Historically, the title comes from the Latin comes stabuli (attendant to the stables, literally count of the stable) and originated from the Roman Empire; originally, the constable was the officer responsible for keeping the horses of a lord or monarch.
PoliceThe police are a constituted body of persons empowered by a state, with the aim to enforce the law, to ensure the safety, health, and possessions of citizens, and to prevent crime and civil disorder. Their lawful powers include arrest and the use of force legitimized by the state via the monopoly on violence. The term is most commonly associated with the police forces of a sovereign state that are authorized to exercise the police power of that state within a defined legal or territorial area of responsibility.
Serial killerA serial killer is typically a person who murders three or more persons, with the murders taking place over more than a month and including a significant period of time between them. While most authorities set a threshold of three murders, others extend it to four or lessen it to two. Psychological gratification is the usual motive for serial killing, and many serial murders involve sexual contact with the victim.
Private policePrivate police or special police are law enforcement bodies that are owned and/or controlled by non-governmental entities. Additionally, the term can refer to an off-duty police officer while working for a private entity, providing security, or otherwise law enforcement-related services. These officers do have power to uphold the laws under the discretion of the private company.
InformantAn informant (also called an informer or, as a slang term, a "snitch", "rat", "stool pigeon", "stoolie" or "grass", among other terms) is a person who provides privileged information, or (usually damaging) information intended to be intimate, concealed, or secret, about a person or organization to an agency, often a government or law enforcement agency. The term is usually used within the law-enforcement world, where informants are officially known as confidential human sources (CHS), or criminal informants (CI).
Police officerA police officer (also called a policeman or policewoman, a cop, or less commonly a constable), is a warranted law employee of a police force. In most countries, "police officer" is a generic term not specifying a particular rank. In some, the use of the rank "officer" is legally reserved for military personnel. Police officers are generally charged with the apprehension of suspects and the prevention, detection, and reporting of crime, protection and assistance of the general public, and the maintenance of public order.
Criminal Investigation DepartmentThe Criminal Investigation Department (CID) is the branch of a police force to which most plainclothes detectives belong in the United Kingdom and many Commonwealth nations. A force's CID is distinct from its Special Branch (though officers of both are entitled to the rank prefix "Detective"). The name derives from the CID of the Metropolitan Police, formed on 8 April 1878 by C. E. Howard Vincent as a re-formation of its Detective Branch.
Police stationA police station (sometimes called a "station house" or just "house") is a building which serves to accommodate police officers and other members of staff. These buildings often contain offices and accommodation for personnel and vehicles, along with locker rooms, temporary holding cells and interview/interrogation rooms. Large departments may have many stations to cover the area they serve.
