Short answers, pulled from the story.
The United States Department of Justice was created in 1870, during the presidency of Ulysses S. Grant. President Grant signed the Act to Establish the Department of Justice into law on the 22nd of June 1870, though the office of the attorney general itself dates back to the Judiciary Act of 1789.
The Department of Justice includes the Federal Bureau of Investigation, the U.S. Marshals Service, the Bureau of Alcohol, Tobacco, Firearms and Explosives, the Drug Enforcement Administration, and the Federal Bureau of Prisons, among others. It also oversees eight legal divisions and the United States attorneys' offices for all 94 federal judicial districts.
Under Attorney General Amos T. Akerman and Solicitor General Benjamin H. Bristow, the DOJ prosecuted Klan members vigorously in the early 1870s. By 1871, the department had secured roughly 3,000 indictments and 600 convictions; ringleaders were imprisoned for up to five years at the federal penitentiary in Albany, New York.
The Department of Justice is headquartered in Washington, D.C., at the Robert F. Kennedy Department of Justice Building, commonly called "Main Justice." The building was completed in 1935 from a design by architect Milton Bennett Medary and was renamed in honor of Robert F. Kennedy in 2001.
The DOJ's Latin motto, Qui Pro Domina Justitia Sequitur, is interpreted by the department's own most authoritative opinion as meaning the attorney general "who prosecutes on behalf of justice (or the Lady Justice)." The exact original intended meaning and the date the motto first appeared on the seal have never been definitively established.
The DOJ's total discretionary budget was approximately $35 billion in fiscal year 2022 and roughly $37.5 billion in fiscal year 2023. The department proposed approximately $39.7 billion for fiscal year 2024, with law enforcement, prisons and detention, and state and local grants making up the largest spending categories.