pretty sure this is archived, but I can't be bothered to retrieve it. In point of fact, US gov is not even trying to hide record of calumny heaped on mendacity. The institutional pride been waiting for fan fiction writers to click a clue. Fuck George Clooney's "Hollywood" red scare, fuck Leonardo Di Caprio's J.E. Hoover "biopic", and fuck Kushner's rainbow melodrama--which I regret having paid real US-dollars to rent an orchestra-row seat.

FBI.gov | A Brief History, The Nation Calls, 1908-1923, GD II-GD III cycle

But violence was just the tip of the criminal iceberg. Corruption was rampant nationwide--especially in local politics, with crooked political machines like Tammany Hall in full flower. Big business had its share of sleaze, too, from the shoddy, even criminal, conditions in meat packaging plants and factories (as muckrakers like Upton Sinclair had so artfully exposed) to the illegal monopolies [read: labor unions, not Standard Oil] threatening to control entire industries.
[...]
It happened at the hands of a 28-year-old Ohioan named Leon Czolgosz, who after losing his factory job and turning to the writings of anarchists like Emma Goldman and Alexander Berkman, took a train to Buffalo, bought a revolver, and put a bullet in the stomach of a visiting President McKinley [R].

muh PBS "immigrant experience"

Eight days later, on September 14, 1901, McKinley was dead, and his vice president Teddy Roosevelt [R] took the oval office.

Call it Czolgosz's folly, because this new President was a staunch advocate of the rising "Progressive Movement." Many progressives, including Roosevelt, believed that the federal government's guiding hand was necessary to foster justice in an industrial society. Roosevelt, who had no tolerance for corruption and little trust of those he called the "malefactors of great wealth," had already cracked the whip of reform for six years as a Civil Service Commissioner in Washington (where, as he said, "we stirred things up well") and for two years as head of the New York [!!] Police Department.

Good read: Caleb Carr, The Alienist historical fiction

He was a believer in the law and in the enforcement of that law, and it was under his reform-driven leadership that the FBI would get its start.
[...]
The chain of events was set in motion in 1906, when Roosevelt appointed a likeminded reformer named Charles Bonaparte as his second Attorney General. The grandnephew of the infamous French emperor, Bonaparte was a noted civic reformer. He met Roosevelt in 1892 when they both spoke at a reform meeting in Baltimore [!!]. Roosevelt, then with the Commission, talked with pride about his insistence that Border Patrol applicants pass marksmanship tests, with the most accurate getting the jobs. Following him on the program, Bonaparte countered, tongue in cheek, that target shooting was not the way to get the best men. "Roosevelt should have had the men shoot at each other, and given the jobs to the survivors." Roosevelt soon grew to trust this short, stocky, balding man from Baltimore [!!] and appointed Bonaparte to a series of posts during his presidency.

Soon after becoming the nation's top lawman, Bonaparte learned that his hands were largely tied in tackling the rising tide of crime and corruption. He had no squad of investigators to call his own except for one or two special agents and other investigators who carried out specific assignments on his behalf. They included a force of examiners trained as accountants who reviewed the financial transactions of the federal courts and some civil rights investigators. By 1907, when he wanted to send an investigator out to gather the facts or to help a U.S. Attorney build a case, he was usually borrowing operatives from the Secret Service [not Pinkerton]. These men were well trained, dedicated--and expensive. And they reported not to the Attorney General, but to the Chief of the Secret Service. This situation frustrated Bonaparte, who had little control over his own investigations.

Bonaparte made the problem known to Congress, which wondered why he was even renting Secret Service investigators at all when there was no specific provision in the law for it. In a complicated, political showdown with Congress, involving what lawmakers charged was Roosevelt's grab for executive power, Congress banned the loan of Secret Service operatives to any federal department in May 1908.

Now Bonaparte had no choice, ironically, but to create his own force of investigators, and that's exactly what he did in the coming weeks, apparently with Roosevelt's blessing. In late June, the Attorney General quietly hired nine of the Secret Service investigators he had borrowed before and brought them together with another 25 of his own to form a special agent force. On July 26, 1908, Bonaparte ordered Department of Justice attorneys to refer most investigative matters to his Chief Examiner, Stanley W. Finch, for handling by one of these 34 agents. The new force had its mission—to conduct investigations for the Department of Justice—so that date is celebrated as the official birth of the FBI.
[...]
During its first 15 years, the Bureau was a shadow of its future self. It was not yet strong enough to withstand the sometimes corrupting influence of patronage politics on hiring, promotions, and transfers. New agents received limited training and were sometimes undisciplined and poorly managed. The story is told, for example, of a Philadelphia [Iziat's Baltimore "suburb" !!] agent who was for years allowed to split time between doing his job and tending his cranberry bog. Later, a more demanding J. Edgar Hoover reportedly made him chose between the two.

Still, the groundwork for the future was being laid. Some excellent investigators and administrators were hired (like the Russian-born Emilio Kosterlitzky), providing a stable corps of talent. And the young Bureau was getting its feet wet in all kinds of investigative areas--not just in law enforcement disciplines, but also in the national security and intelligence arenas.