The FBI was official on July 06, 1908
The FBI’s first ‘lab’ as created November 24, 1932.
The FBI’s first major case using their new ‘lab’ was the LINDBERGH BABY case. The kidnapping was March 1, 1932.
On September 19, 1934, Bruno Richard Hauptmann was taken into custody and was indicted for extortion a week later. His arrest brought an end to the more than two-year-long investigation into the kidnapping and murder of Charles Augustus Lindbergh, Jr., the 20-month old son of famous aviator Charles Lindbergh.
The FBI ‘lab’ proved Hauptmann did it. Since then, it is suspected that the FBI falsified this evidence and that Hauptmann was not guilty.
SO.... I’d say “it’s been like this” since 1932 when the FBI got their own lab so they could falsify evidence and get away with it.
If the FBI really wanted to ensure that JUSTICE was not corrupt, they would always have insisted that the testing be done by independent laboratories.