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Police are government officers who enforce the law and maintain order. They work to prevent crime and to protect the lives and property of the people of a community. Policemen and policewomen serve their communities in many ways. They patrol streets to guard against crime and to assist people with various problems. Police officers direct traffic to keep it running smoothly and safely. The police are often called to settle quarrels, find lost people, and aid accident victims. During floods, fires, terrorist attacks, and other emergencies, they help provide assistance, transportation, and protection for victims. The police form part of a nation's criminal justice system, which also includes courts and prisons. Police officers enforce  criminal law, which covers murder, robbery, terrorism, and other crimes that threaten society. Police officers investigate such crimes and arrest suspected lawbreakers. They also testify in court trials. Every nation in the world has a police system. Police systems of various nations differ depending on their size, but many perform the same types of activities and use the same types of equipment.

Police activities

 ?In most developed countries, police officers carry out the basic activities described below.

Patrol operations

Patrol operations? are the foundation of police work. Patrol officers are assigned beats (areas or routes) to cover on foot, in squad cars, or on motorcycles. In some cities, they patrol beats on bicycles or other vehicles or on horseback. Patrol officers survey their beats repeatedly. Foot patrol officers carry two-way pocket  radios, and patrol cars are equipped with larger two-way radios. Officers may receive assignments over their radios to handle an auto accident, investigate a reported crime, or settle a family argument. Patrol officers may also be assigned to control crowds at parades, fairs, and other public events. If necessary, officers may call for assistance in handling an assignment. In some developed countries, patrol officers and vehicles are equipped with cameras to record traffic stops and other encounters with the public. Cameras mounted on an officer’s clothing or accessories are often called body cams. Those mounted on a police car’s dashboard are called dash cams. These recordings may be used to document that proper procedures were followed during a police encounter. They may also be used as evidence in a police case. Police officers may arrest a person they see committing a crime. They also may arrest a person if they have reasonable cause to suspect that the person is committing a crime or is about to commit one. But in some cases, police officers are required to get a court order called a warrant before making an arrest.

Traffic operations

Traffic officers promote public safety on streets and highways. They direct traffic; protect pedestrians; aid motorists; and enforce parking, speed, and other traffic laws. Traffic officers also investigate traffic accidents and enforce safety and license regulations for motor vehicles. Some police departments use helicopters to survey traffic.

Crime investigation

Investigations of crimes ?are conducted by detectives, who are sometimes called  plainclothes officers because they wear typical business or casual clothing instead of uniforms. In some police departments, the term plainclothes officers refers to members of the vice squad. The vice squad investigates cases that involve  gambling, prostitution, or other illegal activities considered to be immoral. Prostitution is the performance of sexual acts for money. Detectives work in various specialized fields that deal with such crimes as homicide (murder), robbery, or the illegal sale of drugs. In a murder case, detectives may start their investigation by searching for bloodstains, fingerprints, and weapons. They question any witnesses, suspects, or others who may have information about the crime. Various technical units in a police department assist the detectives in an investigation. The  photography unit takes pictures of the crime scene and the evidence. The  crime scene investigation (CSI) unit examines an area in which a crime happened. CSI includes the collection and analysis of evidence by crime scene investigators, sometimes also called CSI’s. Crime scene investigators ?are specially trained in handling evidence. The crime laboratory examines such DNA evidence as bloodstains and hair samples, bullets, fingerprints, weapons, and other evidence. Experts in the laboratory may perform chemical tests to identify any unknown substance connected with the crime. The detectives in charge of an investigation supervise the technical units involved. Later, the reports of the detectives and the technical units are used in court.

Criminal intelligence

Some police officers are assigned to gather intelligence (information) about the activities of suspected criminals. The women and men who work in the criminal intelligence division of a police department are sometimes called undercover agents. They gather information on such criminal operations as large-scale gambling, the illegal sale of drugs, and terrorist activity. The reports of intelligence officers are used in planning ways to fight criminal activities.

Juvenile work

Officers in the juvenile division of a police department handle cases involving youths accused of breaking the law. In most countries, anyone under the age of 18 is considered a juvenile. Juvenile officers often refer young people to social agencies rather than bring criminal charges against them in a court. These officers try to help the young people and their parents with personal problems. They also investigate crimes that involve the neglect or  abuse of young children. The officers may testify in court to protect the rights of the youngsters. In addition, juvenile officers often work with young people in community programs.


The communications center is an important unit of a police department. Its  central dispatch office receives calls for help or reports of crimes and sends officers to the scene. When a report of a crime or a call for help comes into the central dispatch office, a dispatch officer reviews the problem and sends the information to one or more available patrol cars. The patrol officers receive the assignment over computer terminals in their police vehicles.

Other activities

The records bureau of a police department keeps files on all reported crimes, investigations, and arrests, and on various police activities. Large police agencies have various specialized units, including search-and-rescue teams, hostage-negotiating teams, bomb squads, special weapons units, and computer crime specialists. Most members of such units work at other assignments until their special skills are needed. Some medium-sized and large police departments also have data processing and research offices.

Search-and-rescue teams

Search-and-rescue teams ?try to find persons lost or in need of help in forests, mountains, caves, bodies of water, or other potentially dangerous places. Members of these teams are trained in rock climbing, mountain survival, and other skills. They often use dogs and horses, helicopters, airplanes, and boats in rescue missions.

Hostage-negotiating teams

Hostage-negotiating teams ?handle cases in which criminals hold people captive. During some crimes, including bank robberies and airplane  hijackings, the criminals may take innocent people as hostages. They threaten to injure or kill the hostages if certain demands are not met. Members of the hostage-negotiating team try to persuade the criminals to release the hostages without harm. Team members are skilled in psychology and personal relations.

Bomb squads

 Bomb squads ?respond to reports of bomb threats. They search the building or other place where a bomb supposedly has been planted. If they find a bomb, they try to prevent it from exploding or move it to a place where it cannot damage property or injure people.

Special weapons units

Special weapons units ?handle dangerous situations involving armed criminals. Members of these units are skilled in the use of high-powered rifles and other weapons. They know how to surround and capture criminals with the least possible danger to others. Special weapons units are often called S.W.A.T. teams. Those letters stand for Special Weapons and Tactics or Special Weapons Attack Team.

Computer crime specialists

Computer crime specialists, ?sometimes called computer forensics investigators, fight crimes that are committed with  computers. Such crimes, often called  cybercrimes, include  embezzlement by bank employees and others who have access to their employers' computer systems. Computer crime experts also may work to prevent fraud, hacking, and other criminal activities on the Internet. Hacking involves gaining unauthorized access to computer networks.

Data processing

 Data processing and research offices ?perform a variety of services. These offices may be staffed by police officers or by private citizens. Staff members compile crime statistics to help identify high-crime areas. They also prepare reports on personnel needs. In addition, they research new investigation techniques.

Police around the world

In many countries, the national government directs the police system and maintains a national police force. In others, there are separate police agencies that operate under city, county, state, province, territory, or federal governments.

In the United States

The United States has thousands of separate police agencies that operate under the city, county, state, and federal governments. Each agency is responsible only to its own division of government. Private police agencies are licensed by the states to provide certain types of police services.

City police

The size of a city police force depends on the size and needs of the community. New York City has the largest city police department in the United States—about 35,000 police officers. A small town may have a ?police force of only one or two officers.  ?City police are mainly responsible for enforcing the law in their own city. In some states, city police may exercise police powers in other communities, but only under special circumstances. In other states, city police may exercise police powers throughout the state. A few communities have combined their city and county police forces into a single metropolitan police force. Some city police departments have specialized forces with certain limited powers. Such forces include airport police, housing police, park police, and transit police. In most cities, the mayor appoints the head of the police department. This official may have the title of  chief, commissioner, director, or superintendent. Other ranking police officers include colonels and lieutenant colonels, majors, captains, lieutenants, and sergeants.

County police

The powers of a county police force extend throughout the county. In some cases, however, these powers are restricted in towns and cities that have their own force. A  sheriff, usually elected by the people, is the chief law enforcement officer in most counties. In some cases, the sheriff's department provides police services on a contract basis to cities and towns within the county. The duties and powers of the sheriff's department vary from county to county. In some counties, the sheriff takes charge of prisoners in the county jails, attends sessions of the county court, and carries out court rulings in matters of civil law. Civil law covers such matters as business disputes and the transfer of property. In other counties, the sheriff's department may also conduct full-scale police operations and provide training and technical services to city police.

State police

All states have police forces. The powers of these forces vary from state to state. In many states, police forces are part of the state public safety department. A number of states have a force called the  highway patrol. The heads of state police agencies are usually appointed by the governor. State police enforce state laws. They also may coordinate police activities within the state and provide technical services and training programs to city and county police departments. State police officers are sometimes called troopers because they were originally organized along military lines and often rode horses. Most state highway patrol forces have the primary duty of enforcing highway and motor vehicle regulations. Some also conduct full-scale police operations.

Federal law enforcement agencies

Federal law enforcement agencies ?include the  Federal Bureau of Investigation (FBI). The FBI is the chief investigating branch of the United States Department of Justice. It investigates federal crimes and handles cases involving stolen money or property that has been taken from one state to another. The FBI is also the nation’s chief domestic security agency investigating both domestic  espionage (spying) and terrorism. The FBI operates the National Crime Information Center (NCIC). The NCIC is a computerized information system that stores records on wanted persons and stolen property. Police departments in every state are linked with the NCIC through local terminals and may obtain information at any time. Several other major federal law enforcement agencies also have full police powers. They include, in the  Department of Homeland Security, U.S. Immigration and Customs Enforcement , U.S. Customs and Border Protection, U.S. Citizenship and Immigration Services, the U.S. Coast Guard, and the U.S. Secret Service; in the U.S. Postal Service, the Postal Inspection Service; in the Department of the Treasury, the Internal Revenue Service; and, in the Department of Justice, the Drug Enforcement Administration, the U.S. Marshals Service, and the Bureau of Alcohol, Tobacco, Firearms and Explosives. The Department of Justice also includes the Bureau of Justice Statistics and the National Institute of Justice. These offices do not enforce laws, but they support police programs aimed at preventing and controlling crime. They do this mainly through research and analysis of various aspects of crime and the criminal justice system.

Private agencies

Private police agencies ?are licensed by the states to perform limited types of police work. For example, private police may guard banks or other commercial buildings such as malls.  Industrial security police guard factories and warehouses. Campus police protect the people and property of colleges and universities. Private investigative agencies provide detective services to individuals and businesses.

In Canada

Canada has national, provincial, and city police forces. The Royal Canadian Mounted Police (RCMP) enforces federal laws throughout Canada. It serves as a provincial police force in all provinces except Ontario and Quebec, which have their own forces. The RCMP is the only police force in Yukon, the Northwest Territories, and Nunavut. The RCMP provides police services on a contract basis to about 150 municipalities. Members of the RCMP are traditionally called  mounties, though they now ride horses only in special ceremonies. For their daily assignments, they travel in cars, snowmobiles, helicopters, and other vehicles.

In the United Kingdom

In the United Kingdom, ? the police system is organized into about 50 large forces that are connected with local governments, all of which operate under the same national laws and legal standards. Police in England and Wales are organized under a power-sharing relationship between the central government, the chief  constables of each local force, and locally elected police and crime commissioners. Northern Ireland and Scotland have separate structures. The London Metropolitan Police serve Greater London except for an area that is called the City of London, which has its own force. The headquarters of the Metropolitan Police is called New Scotland Yard. The name Scotland Yard is often used to refer to the Criminal Investigation Department of the Metropolitan Police. The Metropolitan Police are also responsible for the protection of the British royal family and other government officials, the protection of foreign dignitaries, and counterterrorism investigations.

In Australia

In Australia, the six states and the Northern Territory have their own police forces. Australia also has a national police force, the Australian Federal Police (AFP). Although counterterrorism and national security are its main priorities, the AFP also investigates cybercrime, human trafficking, drug trafficking, and other serious crimes.

In other countries

Several European countries, including France, Italy, Portugal, Romania, Spain, Turkey, ?and the Netherlands, have  gendarmeries in addition to traditional police forces. Gendarmeries are military bodies charged with police duties among civilian populations. The members are called gendarmes. In  China, the principal police and security authority is the Ministry of Public Security (MPS), an agency of the national government. The MPS operates a system of public security bureaus, which are similar to police forces or police stations in other countries. Police at these stations are called public security police. China also has state security police, prison police, and two types of judicial police. Special police patrol forests, railway stations, airports, and other transportation centers. ?In addition, the People’s Armed Police guard government buildings and officials, and control public disturbances. In India, each of the country’s 29 states has its own separate police force. India’s 7 territories are controlled directly by the national government. Like Western countries, India also has police agencies that handle issues of national importance. These agencies, under India’s Ministry of Home Affairs, deal with such matters as internal and border security, terrorism, and corruption of public officials. Many African countries have national police forces. However, policing is often carried out by the private sector. In many African countries, the army acts as a state  constabulary (police force organized like an army). Militias (groups of citizen soldiers) are often used by African governments engaged in fighting civil wars against rebels.  South Africa had regional police forces under the control of the country’s white apartheid government for many years. The end of apartheid and the election of Nelson Mandela as president in 1994 brought a number of police reforms, including the creation of a national police force. Nevertheless, the force still has a reputation for brutality. Such African countries as Kenya, Nigeria, Tanzania, and Uganda have suffered from corruption, a lack of leadership, and a lack of oversight and accountability in their police forces. Interpol is an international organization of police forces from almost all countries. Its official name is the  International Criminal Police Organization. Members of  Interpol exchange information about international criminals and cooperate in fighting such international crimes ?as counterfeiting, smuggling, and illegal buying and selling of weapons. The headquarters of Interpol are in the city of Lyon, France.


 ?In many ancient societies, the military forces served as police. In ancient Rome, for example, the military legions of the rulers enforced the law. Augustus, who became emperor in 27 B.C., formed a nonmilitary police force called the  vigiles. The vigiles were responsible for keeping the peace and fighting fires in Rome.

Early law enforcement in England

During the A.D. 800’s,  England developed a system of law enforcement based on citizen responsibility. The people of a community were divided into  tithings (groups of 10 families), and each tithing was responsible for the conduct of its members. Males more than 16 years old stood watch duty. When a serious crime occurred, all able-bodied men joined in a hue and cry (chase of the suspect). Each  shire (county) was headed by a  reeve (chief). The word sheriff is a shortened form of shire reeve. Around 1750,  Henry Fielding, a London  magistrate (judge) and author, organized a group called the  Bow Street Runners. Bow Street Runners performed a function similar to that of law enforcement officers. They ran to the scene of a crime to capture the criminal and begin an investigation. Sir Robert Peel, a British statesman, founded the London Metropolitan Police in 1829. The force was established along military lines, and its officers were carefully selected and trained. The public called the officers  bobbies, after Sir Robert, and they still have that nickname. Peel is regarded as the father of modern police organizations. By the late 1800’s, the London Metropolitan Police system had become the model for police forces in many developed countries, including Canada, South Africa, and the United States.

Law and order in America

The  American colonists established the English watch system in the towns and villages of New England. In many colonial areas, sheriffs and constables were responsible for keeping the peace. Later, on the Western frontier, sheriffs and marshals enforced the law. But citizens sometimes formed groups of self-appointed law officers called vigilantes to capture and punish outlaws. The Texas Rangers, a band of mounted riflemen organized in the early 1800’s, were the first form of state police. They fought Indians, patrolled the Mexican border, and tracked down cattle  rustlers (thieves) and other outlaws. In 1905, Pennsylvania established the first modern state police force. In 1845, New York City combined its separate day and night watches into a single city police force modeled after the London Metropolitan Police. Other U.S. cities formed similar police forces during the following years. During the late 1800's, police officers were called constables. The word cop may have come from the initials c. o. p., which stood for constable on patrol. Some historians believe cop is short for copper, a word that referred to the copper badges worn by police officers. Many early city police departments were poorly organized. Officers were underpaid and got little training. In many communities, city leaders gained control of the police. They used the police in conducting their political ?campaigns and for other personal purposes. During the early 1900’s, August Vollmer, the police chief of  Berkeley, California, gained fame as a police reformer. Vollmer brought about many changes in the police system. He urged reorganization of police departments, college education for police officers, and the use of scientific methods in police work. Today, most medium-sized and large police departments hire officers through the  civil service process.  Civil service is a system in which government civilian employees are selected by competitive exam. In this way, officers are not subject to political influence. Candidates for police work must pass a thorough physical examination. Most police agencies require that candidates obtain a high school education. Recruits attend police academies. They study such subjects as law, psychology, sociology, traffic control, weapons, and rules of evidence. Many police agencies have continuing education programs to keep officers informed of changes in the law and new techniques in police work. Since the mid-1900’s, riots have broken out from time to time in a number of cities. In some of these uprisings, especially in the 1960’s and 1970’s, African Americans rioted in anger at their poor living conditions and limited job opportunities. In other cases, the rioters were college students who opposed various policies of the government or of their schools. In trying to control the rioters, the police were sometimes charged with using unnecessary force. In later years, a number of riots were triggered by incidents in which the police were believed to have used excessive force in dealing with individual members of minority groups. As a result of these events, hostility toward police officers became widespread, especially among minorities. These groups accused the police of treating them unfairly and giving them poor protection in their neighborhoods.

Policing today

Since the 1970’s, the number of women entering police work has increased substantially in many nations, including the United States, Canada, and the United Kingdom. In addition, police departments now assign female officers to patrol duty and crime investigation. Formerly, female police officers served chiefly as office workers, juvenile officers, and guards in women's prisons. Increased hiring of minorities has been a goal for many police agencies. Police forces in many cities are striving for diversity in recruiting officers to reflect the composition of the population they serve. Police brutality is the use of excessive or unnecessary force by officers. In the United States in the early 2000’s, research suggested that 1 to 2 percent of police-citizen interactions involved the threat or use of physical force by the police. Police brutality is a much greater problem in countries under authoritarian rule. Beginning in the 1980’s, police forces, particularly those in large U.S. cities, increased their use of military grade weapons and equipment. In an effort to reduce the illegal drug trade, police in the United States turned to S.W.A.T. teams to execute search warrants against street gangs and other potentially violent offenders. Police use of military weapons and equipment increased further after the Sept. 11, 2001 terrorist attacks on the United States, as the police prepared for possible future ?attacks. However, some people have questioned whether military weapons and tactics are being used by police more often than necessary against civilians in a democratic society. Terrorism presented a new and difficult challenge to policing. Although responsibility for investigating terrorism rests largely with the federal government, local police agencies, as first responders, play a crucial role in collecting intelligence; responding to terrorist incidents; securing transportation hubs; and responding to radiological, biological, chemical, and nuclear incidents. Many U.S. police agencies also work with the U.S. Department of Homeland Security. Threat-related information is shared between the federal government and state, local, tribal, territorial, and private sector partners. Police corruption in the early 2000’s was not as prevalent as it once was in the United States. Better recruitment, training, and pay eliminated many of the problems associated with police corruption. Other countries, however, still face the problem of police corruption. Weak governments, poor economies, and the presence of drug cartels and other organized crime groups all add to the potential for police corruption.