Police officers, detectives, and criminal investigators typically do the following:

• Enforce laws
• Respond to emergency and nonemergency calls
• Patrol assigned areas
• Conduct traffic stops and issue citations
• Search for vehicle records and warrants using computers in the field
• Obtain warrants and arrest suspects
• Collect and secure evidence from crime scenes
• Observe the activities of suspects
• Write detailed reports and fill out forms
• Prepare cases and testify in court

Police officers pursue and apprehend people who break the law. They then warn, cite, or arrest them. Most police officers patrol their jurisdictions and investigate suspicious activity. They also respond to calls, issue traffic tickets, and give first aid to accident victims.

Detectives perform investigative duties, such as gathering facts and collecting evidence.

The daily activities of police and detectives vary with their occupational specialty, such as canine units and special weapons and tactics (SWAT). Job duties differ at the local, state, or federal level. Duties differ among federal agencies because they enforce different aspects of the law. Regardless of job duties or location, police officers and detectives at all levels must write reports and keep detailed records that will be needed if they testify in court. Most carry law enforcement tools, such as radios, handcuffs, and guns.

State and Local Law Enforcement

Uniformed police officers have general law enforcement duties. They wear uniforms that allow the public to easily recognize them as police officers. They have regular patrols and also respond to emergency and nonemergency calls. During patrols, officers look for any signs of criminal activity and may conduct searches and arrest suspected criminals.

Some police officers work only on a specific type of crime, such as narcotics. Officers, especially those working in large departments, may work in special units, such as horseback, motorcycle, canine corps, and special weapons and tactics (SWAT). Typically, officers must work as patrol officers for a certain number of years before they may be appointed to a special unit.

Some agencies, such as public college and university police forces, public school police, and transit police, have special geographic and enforcement responsibilities.

State police officers, sometimes called state troopers or highway patrol officers, have many of the same duties as other police officers, but they may spend more time enforcing traffic laws and issuing traffic citations. State police officers have authority to work anywhere in the state and are frequently called on to help other law enforcement agencies, especially those in rural areas or small towns.

Transit and railroad police patrol railroad yards and transit stations. They protect property, employees, and passengers from crimes such as thefts and robberies. They remove trespassers from railroad and transit properties and check IDs of people who try to enter secure areas. 

Sheriffs and deputy sheriffs enforce the law on the county level. Sheriffs' departments tend to be relatively small. Sheriffs are usually elected by the public and do the same work as a local or county police chief. Some sheriffs' departments do the same work as officers in urban police departments. Others mainly operate the county jails and provide services in local courts. Police and sheriffs' deputies who provide security in city and county courts are sometimes called bailiffs.

Detectives and criminal investigators are uniformed or plainclothes investigators who gather facts and collect evidence for criminal cases. They conduct interviews, examine records, observe the activities of suspects, and participate in raids and arrests. Detectives usually specialize in investigating one type of crime, such as homicide or fraud. Detectives are typically assigned cases on a rotating basis and work on them until an arrest and trial are completed or until the case is dropped.

Fish and game wardens enforce fishing, hunting, and boating laws. They patrol fishing and hunting areas, conduct search and rescue operations, investigate complaints and accidents, and educate the public about laws pertaining to the outdoors. Federal fish and game wardens are often referred to as Federal Wildlife Officers.

Federal Law Enforcement

Federal law enforcement officials carry out many of the same duties that other police officers do, and they also have jurisdiction over the entire country. Many federal agents are highly specialized. The following are examples of federal agencies in which officers and agents enforce particular types of laws.

• Federal Bureau of Investigation (FBI) agents are the federal government's principal investigators, responsible for enforcing more than 200 categories of federal statutes and conducting sensitive national security investigations.
• Drug Enforcement Administration (DEA) agents enforce laws and regulations relating to illegal drugs.
• United States Secret Service uniformed officers protect the President, the Vice President, their immediate families, and other public officials. Other Secret Service agents investigate financial crimes.
• Federal Air Marshals provide air security by guarding against attacks targeting U.S. aircraft, passengers, and crews.
• U.S. Border Patrol agents protect the U.S. land and sea boundaries.

See the Contacts for More Info section for additional information about federal law enforcement agencies.