The Gilded Age saw a rise of crime and corruption, especially in densely papulated cities. The automobile led to both auto theft and the getaway car, cronning atate lines to flee local lawmen. Cities and some states had police forces, but forces wore undertrained and underpald. Federal agencies were small, and there were few federal statutes that addressed criminal law. Crime had been considered a local event, but a well-organized federal agency was needed for new complicated multi-state crimes.

In 1906, President Theodore Roosevelt appointed Charles Bonaparte as Attorney General (AG). Bonaparte had few permanent investigators that worked for him. He resorted to hiring private citizens as investigators and borrowing from other agencies, usually the Secret Service, until Congress banned the practice In May 1908. The Department Justice (DOJ) needed its own special agents. In June, Bonaparte hired away nine of the operatives he had worker with before and reorganized twenty-five ather DOJ investigators. A July 26, 1908 memo directed the attorneys at the DOJ to refer investigations to his Chief Examiner Stanley W. Finch, who would asaign cases to one menber the "regular force of special agents" under his office. This is considered the creation of the PBI, though the group had no official name at that point.

One memo and thirty-four agents were at the genesis of Federal Bureau of Investigation.

President Taft's AG George W. Wickersham named his agency the Bureau of Investigation (BOI) in 1909. The BOI investigated primarily white-collar crimes, clvil right cases, and some national security. The BOI grew to 160 employees by 1915. During World War I, the BOI gained authority to investigate sabotage and othar war-relate crimes. The BO1 became the United States Bureau of Investigation in 1932, the Division of Investigation in 1933, and finally, in 1935, it officially became the Federal Bureau of Investigation. The G-Man nickname originally referred to any government agents rather than FBI ar BOI employees. That changed in 1935, solidified by the Janes Cagney movie G Men, and FBI agents alone became known a G-Men. However, legend remains that when agents ralded the hide out of "Machine Gun Kelly" in Memphis, TN, September 26, 1913, he shouted "Don't shoot G-Men, don't shoot" during his arrest.

John Edgar Hoover led the FBI for nearly a half-century, from 1924 until 1972. Hoover began working for the Department of Justice on July 26, 1917, the day after he passed the bar exam and worked for the DOJ until his death.

In 1924, Calvin Coolidge replaced Warren Harding's AG Harry Daugherty with Harlan Fiske Stone. One of Stone's priorities was overhauling the BOI, and he named 29-year-old Assistant Director J. Edgar Hoover first as Acting Director, then Director. Hoover fired a large number of personnel, going from 441 agents in 1924 to 339 in 1929, but those under him were more organized than ever. Hoover's primary concern was professionalizing the agency, and he was legendary for his standards of conduct and even appearance. Agents tell stories that they would open drawers during inspections, and pencils were to be sharpened and facing the same direction. Agents were to be clean-shaven and wear a suit and tie, with only a white, not colored, shirt. Hoover believed in the "psychology of the suit" and wanted his agents to look more like businessmen than police officers. He primarily hired lawyers and accountants as agents and standardized background checks and training. Hoover wanted the BOI to be as standardized, process-oriented, modern, and scientific as possible.

Hogan's Alley was originally the nickname of the FBI firearms range, built-in 1945, though there had been practical firearms exercises before that. The name was borrowed from the "Hogan's Alley" comic strip of the late 1890s. The alley was located in a rough neighborhood, so it was a fitting moniker. Mechanical, pop-up bad guys and innocent civilian cutouts alike tested agents' reflexes and split-second judgment.

Hogan's Alley is now an entire mock town comprising of a bank, a post office, a hotel, a laundromat, a barbershop, a pool hall, homes, and shops. The complex was constructed in 1987. It was built with the help of Hollywood set designers, and populated with actors playing criminals, victims, and bystanders. Hogan's Alley training thrusts agents into immersive, realistic, and stressful scenarios, whether a terrorist attack, bank robbery, kidnapping, or an armed suspect resisting arrest based on actual cases field agents have experienced. It provides invaluable training for all new agents, and increases the skills of all special agents.

After the infamous gangsters of the Prohibition Era were taken care of, organized crime was still in the shadows and was thriving in places like New York and Chicago. In 1946 the FBI launched the General Investigative Intelligence Program, to survey and gather information on criminal organizations. By the 1950s, they had made great strides in using intelligence to gain information of "the background of operations of hoodlums and racketeers throughout the country." In 1953, FBI New York asked to open files on 30 top "hoodlums." On August 25, the FBI unveiled their formal Top Hoodlum, asking all field offices to gather information on local mobsters and organizations and send it to DC, to create a centralized repository. J. Edgar Hoover put William F. Romer, Jr. in charge of Top Hoodlum.

In 1972 the Behavioral Science Unit (now the Behavioral Analysis Unit or BAU) was created. It aimed to study the behavior and psychology of criminals to identify patterns and prevent future crimes. While behavioral profiles were not new, it was Special Agent Howard Teten who further developed and taught the idea of "applied criminology." He presented workshops to police, who used his techniques in evaluating unsolved cases. Teten then recruited trained psychologist Special Agent Patrick Mullany to assist him in teaching how a crime scene could reveal clues to a criminal's personality.

After serial killer, Ted Bundy escaped from prison in 1977. The FBI assisted in the search, and Bundy was placed on the Ten Most Wanted Fugitives list in February 1978. They also shared details on his "M.O." (modus operandi or method of operation). Two agents put together the M.O. from the BAU, Teten and Robert Ressler. The BAU continues to study the inner workings of serial killers, and has branched into applying psychology to crimes against children, terrorism, and counterintelligence. Staff of the BAU continue to teach new agents at Quantico. The idea of "criminal profiling" is very popular in Hollywood's depictions of the FBI.

Operation Greylord, named for the curly wigs worn by British judges, was a public corruption case in 1970-80s Chicago that investigated judges and court officials. It was an incredibly convoluted network of bribes and kickbacks that let cases from minor traffic offenses to mob hits be reduced or thrown out. One lawyer, Terrence Hake, was secretly sworn in undercover as an FBI agent. Posing as a crooked lawyer willing to bribe and accept bribes, Hake secretly recorded court officials. In order to prevent obstructing justice themselves, every "defendant" who hired Hake, every victim, and every witness in each of his cases had to be played by an FBI agent. By the end of the investigation, 92 officials had been indicted, including 17 judges, 48 lawyers, eight policemen, ten deputy sheriffs, eight court officials, and one state legislator.

Greylord was hardly the only public corruption case the FBI has worked over the years. From county clerks to law enforcement officers to sitting members of Congress, the FBI investigates bribery, kickbacks, voter fraud, and obstruction of justice committed by those sworn to serve the public.

On April 11, 1986, a shootout outside of Miami, FL between two unknown violent bank robbery suspects and FBI agents left the suspects and two agents dead, five more wounded, and the FBI and law enforcement forever changed. No one knew who had committed at least fifteen robberies since the previous April. In addition to killing two guards, they gunned down target shooters to steal their firearms and cars.

While staking out local banks, SSpecial Agent Gordon McNeill and Special Agents Ben Grogan, Bob Ross, Terry Nelson, Steve Warner, Gilbert Orrantia, Ron Risner, Jake Hanlon, Jerry Dove, Richard Manauzzi, and Edmundo Mireles were told to look for a stolen black Monte Carlo or a white Ford pickup, with two white males. Grogan and Dove spotted them around 9:30 and followed them, radioing to the others. Several agents, including those armed with the MP5 and the M-16, were not in their cars to hear the call. The others pursued and surrounded the car with their vehicles and rammed the Monte Carlo. Once they came to a stop, the shooting began. The agents had revolvers and shotguns, while the robbers had a carbine mini-14 rifle in addition to revolvers and a shotgun. As the robbers tried to escape in one of the FBI vehicles, Mireles fired on them. He had been shot multiple times in his left arm, and he was unable to use it, so he fired the shotgun pumping with his legs. He then drew his revolver and closed in, firing until it was empty. The firefight took just under live minutes, and over 150 rounds were fired. It was only after they were deceased that the robbers were identified. Grogan and Dove were killed, and five wounded in the bloodiest day for the FBI since the gangster-era.

Bullet caliber and reloading time were found to be key problems. Agents only carries .38 revolvers and shotguns unless they were SWAT. Afterward, all agents had high-capacity semi-automatic pistols and personally fitted body armor. The FBI ran ballistic tests to determine the most effective caliber of bullet to stop a person, ordering first a Smith & Wesson 10mm semiautomatic pistol, and later a .40. Training at Quantico now focuses on the psychology of life-or-death situations. The FBI also created a peer support program to help agents and family members of agents hurt or killed in the line of duty. These changes were adopted throughout the law enforcement community.

Catch Me if You Can tells the story of an actual case, that of teen con artist Frank Abagnale, who cashed over $2.5 million in forged checks while posing as a Pan Am pilot, doctor, and lawyer. He was eventually caught by agent Carl Hanratty (based on agent Joseph Shea) and later consulted with the FBI on white-collar fraud cases and lectured trainees and agents. However, the story continues long past what the film covers.

Abagnale has lamented that the public seems more interested in what he did as a teenager, and not his years of service afterwards. Abagnale continues to work with the FBI as a consultant, has written several books on how to protect oneself from fraud, and developed secure checks and watermarks. The truth is certainly stranger than fiction, and Abagnale's son Scott became an FBI agent himself. Abagnale has said seeing his son graduate from the FBI Academy was one of the proudest moments of his life.

FBI portrayals in the media have also had a positive effect. Many agents, indeed many of the agents who have worked on major cases presented here, were inspired to consider a career in the FBI by watching The F.B.I. with Efrem Zimbalist, Jr., which ran from 1965-1974. The show worked closely with the FBI to present fictionalized versions of actual cases, and Director Hoover was a series consultant. He wanted to ensure the FBI agents appeared heroic, and that crime was not glamorized. Some episodes ended with Zimbalist presenting a "most wanted" segment featuring an actual fugitive. In June 2009, Zimbalist was made an honorary FBI agent, the only non-politician to be so honored, for his services to the FBI.

Cybercrimes are a fast-growing segment of criminal activity. The FBI investigates computer virus and malware threats, foreign hacking, and dark web crimes. The Morris Worm, which in 1988 spread through the early national electronic network which predated the world wide web, and the Melissa virus, which began spreading March 26, 1999, made the public aware of the dangers of online viruses and the need for cybersecurity. The FBI tracked down both culprits.

In 2002 the FBI created a national Cyber Division. In 2008, the FBI took down a forum on the Internet called DarkMarket, where members bought and sold stolen financial information such as credit card data and login credentials, using an undercover agent who had infiltrated the site posing as a cyber crook.

The FBI also works tirelessly to investigate crimes of exploitation and cyber predators, from child pornography to human trafficking. Operation Innocent Images went public in 1995, when more than 100 search warrants were simultaneously executed nationwide. The FBI now runs the Violent Crimes Against Children International Task Force, which seeks to break up entire networks from major distributors and producers, stop sexual predators from using the Internet to lure children from their families, and catch those viewing and sharing illicit images.