Understanding Federal Law Enforcement in the United States Part 4—Federal Bureau of Investigation

This is the fourth in a six-part series examining major federal law enforcement agencies through a research-grounded lens, assessing each agency across the same core categories.

When a cyberattack cripples a hospital’s computer network, when a public corruption investigation topples a sitting mayor, when a terrorist plot is disrupted before it reaches execution, or when a fugitive on the Ten Most Wanted Fugitives list is tracked across international borders, the same three letters appear in the headlines: FBI. The Federal Bureau of Investigation (FBI) occupies a unique position in American law enforcement—it is simultaneously the country’s principal federal criminal investigative agency, a domestic intelligence service, and an international law enforcement partner. With its jurisdiction spanning more than 200 categories of federal crime, no other agency in the federal system operates as broadly.

Yet the FBI’s breadth of authority has always made it a lightning rod. The same agency that disrupted the MS-13 gang network and dismantled ransomware operations also carries the historical weight of COINTELPRO—the counterintelligence program that surveilled civil rights leaders—and the more recent controversies surrounding the Bureau’s Crossfire Hurricane investigation. Since early 2025, the FBI has undergone significant organizational restructuring under Director Kash Patel, including the removal of senior career officials; large-scale personnel transfers out of the Washington, D.C. region; and the redeployment of agents toward immigration enforcement and violent crime. These changes have placed the Bureau at the center of debate over whether its mission is sharpening or being redirected.

Creation and Legislative Origins

The FBI is the oldest of the three Department of Justice (DOJ) agencies covered in this series. Its origins lie not in a sweeping piece of legislation but in a bureaucratic workaround. In the early 1900s, the DOJ had no permanent investigative force of its own and borrowed detectives from the Secret Service. When Congress prohibited the practice in 1908, Attorney General Charles J. Bonaparte created a small force of special agents within the DOJ. On July 26, 1908, Bonaparte ordered those agents to report to Chief Examiner Stanley W. Finch, effectively founding the FBI.

Designated the Bureau of Investigation in 1909, the force operated with a small staff and limited jurisdiction. Its early caseload included land fraud, antitrust violations, and enforcement of a 1910 federal law that made it a federal crime to transport individuals across state lines for prostitution or other illicit purposes. World War I expanded its responsibilities into espionage and sedition cases. The Bureau’s transformation into a modern agency began in 1924 under J. Edgar Hoover, who professionalized the organization by establishing qualification standards, creating a centralized fingerprint repository, and building the FBI Laboratory. Renamed the Federal Bureau of Investigation in 1935, the Bureau grew dramatically under Hoover’s 48-year tenure—a period that saw both its rise to institutional prominence and, as congressional investigations later revealed, significant abuses including surveillance of political activists, journalists, and civil rights leaders.

Enacted by Congress in 1968, Public Law 90-351 required Senate confirmation of FBI directors and imposed a 10-year term limit. That framework remains in place today, with the current director confirmed on a 51-49 vote in February 2025.

The attacks of Sept. 11, 2001, marked another transformative moment. The 9/11 Commission found that the FBI’s pre-9/11 structure prioritized prosecuting crimes after they occurred rather than preventing attacks. Congress responded with the USA PATRIOT Act of 2001, which expanded surveillance and intelligence-gathering authorities, and the Intelligence Reform and Terrorism Prevention Act of 2004, which created the Office of the Director of National Intelligence. The FBI reoriented significant resources toward counterterrorism and counterintelligence—a shift that reshaped the Bureau’s workforce, budget, and institutional culture.

Mission

The FBI’s mission is “to protect the American people and uphold the Constitution of the United States.” Where other federal law enforcement agencies are organized around specific operational domains, the FBI’s mandate is defined by breadth. The Bureau is the lead federal agency for counterterrorism, counterintelligence, and cybercrime investigations. It also investigates public corruption, civil rights violations, organized crime, white-collar crime, and violent crime and shares concurrent jurisdiction with the Drug Enforcement Administration (DEA) over narcotics offenses under the Controlled Substances Act. No other federal agency spans as many criminal and national security categories.

The FBI is also a member of the U.S. Intelligence Community, reporting to both the Attorney General and the Director of National Intelligence. This dual role has been a defining (and sometimes contentious) feature since the post-9/11 reforms. In practical terms, the FBI has two missions: to collect information that stops something from happening and to gather evidence to prosecute something that has already occurred. These missions operate under different legal rules.

How the FBI prioritizes its many responsibilities has varied across administrations. Counterterrorism dominated in the years following 9/11; more recently, directors pointed to growing threats from nation-state cyber actors as a top concern. Since January 2025, the current administration has directed the FBI to prioritize violent crime and immigration enforcement. Patel outlined four priorities: “crush violent crime, defend the homeland, restore public trust, and enforce organizational accountability.” The FBI’s Joint Terrorism Task Forces have been directed to support immigration enforcement in partnership with Department of Homeland Security (DHS) components, and the Bureau has reported making over 25,000 immigration-related arrests since January 2025. It also created new Homeland Security Task Forces co-led by the FBI and Immigration and Customs Enforcement (ICE)’s Homeland Security Investigations.

The scale of this shift became clearer in October 2025, when data revealed that approximately one-quarter of the Bureau’s roughly 13,000 special agents (about 3,000) were assigned to immigration enforcement for at least half of their working time—a number that climbed to 40 percent in the largest field offices. The reassignment generated sharp debate. Patel and then-Attorney General Pam Bondi argued that the work complemented the Bureau’s core missions, while critics raised concerns that diverting agents from long-term investigations—such as counterintelligence, cybercrime, and child exploitation cases—could produce delayed consequences. The FBI was part of a broader government-wide redeployment, with the DEA, the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), the U.S. Marshals Service, and other agencies shifting personnel toward immigration operations during the same period.

Whether this reorientation strengthens or dilutes the FBI’s core capabilities remains a subject of active debate—a pattern consistent with other agencies examined in earlier installments of this series.

Scale

According to the Bureau’s fiscal year 2026 budget request, the FBI has over 35,000 direct-funded positions, including approximately 13,600 special agents, 3,300 intelligence analysts, and more than 20,000 professional staff. The Bureau operates through 56 field offices, more than 350 resident agencies, and over 60 international legal attaché offices worldwide. FBI-led task forces incorporate over 9,000 federal, state, local, tribal, and territorial partners.

The Bureau has undergone significant internal restructuring since February 2025. Patel transferred approximately 1,500 employees from the National Capital Region to field offices: about 1,000 to cities designated as high-crime locations and 500 to a satellite facility in Huntsville, Alabama. The Bureau also restructured its reporting lines so that most field offices report to regional branch directors rather than through headquarters.

All six of the FBI’s most senior career executives (plus the heads of multiple field offices) were forced out shortly before Patel’s confirmation. When the administration’s request for a list of all FBI employees who had worked on Jan. 6-related investigations prompted federal lawsuits from agents, the DOJ stated that employees found to have “followed orders and carried out their duties in an ethical manner” during those investigations would not face termination.

Jurisdiction

The FBI’s statutory authority is rooted in 28 U.S. Code § 533, which authorizes the Attorney General to appoint officials to “detect and prosecute crimes against the United States.” Congress has layered additional authorities across dozens of federal statutes, giving the FBI jurisdiction over more than 200 categories of federal crime including terrorism under Title 18, computer fraud under the Computer Fraud and Abuse Act, racketeering under the Racketeer Influenced and Corrupt Organizations Act, civil rights violations, bank fraud, kidnapping, and hundreds more.

Unlike other federal law enforcement agencies whose jurisdictions are shaped by geography, the FBI’s jurisdiction is defined almost entirely by subject matter. The Bureau shares investigative responsibility with numerous other agencies on overlapping matters—narcotics with the DEA, financial crimes with the Secret Service and Internal Revenue Service Criminal Investigation, firearms trafficking with the ATF, and transnational criminal organizations with other DHS components. While this overlapping authority often generates productive collaboration through joint task forces, it can also create friction when multiple agencies pursue parallel investigations.

Many crimes the FBI investigates also violate state law, creating situations where both federal and state prosecutors have authority to bring charges for the same conduct. In practice, federal and state authorities have long coordinated through joint investigations and informal protocols governing who takes the lead. That coordination has come under strain recently—most visibly after an ICE agent fatally shot Renee Good during an immigration enforcement operation in Minneapolis in January. The FBI subsequently assumed sole control of the investigation, cutting state investigators off from evidence. The broader question of when federal agents are shielded from state prosecution under the Constitution’s Supremacy Clause has become one of the most actively contested areas of federal-state relations.

The FBI’s intelligence role gives it authorities that other federal law enforcement agencies do not possess. Under Section 702 of the Foreign Intelligence Surveillance Act (FISA), the FBI may query databases containing communications collected by the National Security Agency (NSA), meaning the FBI can search through communications the NSA has already collected from foreign targets. But those searches sometimes turn up Americans’ phone calls, emails, and texts as well. In 2025, the FBI reported 7,413 queries of U.S. person data under FISA Section 702—a 35 percent increase over the prior year. Civil liberties advocates argue this permits warrantless searches of Americans’ communications, while national security officials say it is essential for identifying threats. Section 702’s statutory authorization expired April 20; however, Congress passed a short-term extension while lawmakers continue to debate reauthorization.

Hiring and Training

The FBI maintains its own hiring pipeline and training infrastructure separate from the Federal Law Enforcement Training Centers used by other federal agencies. All training takes place at the FBI Academy in Quantico, Virginia.

Special agent candidates must:

• Be a U.S. citizen between the ages of 23 and 36
• Hold at least a bachelor’s degree plus two years of professional work experience (or an advanced degree plus one year)
• Pass the Special Agent Selection System—a multi-phase process that includes written assessments, a structured interview, a physical fitness test, a polygraph, a medical evaluation, and a thorough background investigation
• Obtain a Top Secret security clearance

New agents attend the FBI Academy’s Basic Field Training Course, where they receive more than 800 hours of instruction covering federal law, investigative techniques, forensic science, behavioral science, ethics, firearms, defensive tactics, and counterterrorism fundamentals. The course lasts approximately 18 weeks and includes practical exercises in Hogan’s Alley, the Bureau’s mock town designed to simulate real-world law enforcement scenarios. New intelligence analysts attend a separate 12-week program that follows a curriculum consistent with the rest of the U.S. Intelligence Community.

The FBI’s use-of-force policy operates under the DOJ Use of Force Policy, applying the Graham v. Connor (1989) reasonableness standard and the Tennessee v. Garner (1985) framework for deadly force. In practical terms, agents may use only the level of force a reasonable officer would consider necessary under the same circumstances and may use deadly force only when they have a reasonable belief that someone poses an imminent danger of death or serious physical injury. The policy prohibits chokeholds and carotid restraints (except when the deadly force standard is met) and requires de-escalation when feasible. Every use-of-force incident triggers an internal review, and agents receive quarterly use-of-force training alongside firearms requalification. The FBI also manages the National Use-of-Force Data Collection, a voluntary nationwide database created in 2015 as the country’s first comprehensive national dataset.

The FBI also provides training to law enforcement partners through the FBI National Academy, a professional development program for senior officers from state, local, tribal, and international agencies.

Looking Ahead

The next installment examines the second of three DOJ agencies covered in this series: the Bureau of Alcohol, Tobacco, Firearms and Explosives. While the FBI operates under the broadest statutory mandate of any federal law enforcement agency, the ATF is narrowly defined by federal laws related to alcohol, tobacco, firearms, explosives, and arson. While the two agencies occasionally collaborate on investigations involving violent crime and domestic terrorism, their missions, organizational scale, and the public debates surrounding them differ in key ways.

bool(true)

bool(true)

string(3) "100"

Next in this series: Part 5—Bureau of Alcohol, Tobacco, Firearms and Explosives