WASHINGTON (AP) — An association of thousands of FBI agents and other groups are backing a lawsuit filed by three bureau employees who were fired last year for their roles in an investigation into President Donald Trump's efforts to undo the results of the 2020 presidential election. FBI Special Agents have long understood that they are subject to assignment and reassignment at any time based on the needs of the Bureau," the agents association, which serves nearly 12,000 members, wrote in its brief. A brief filed by former senior Justice Department officials says the firings have undermined a "half-century of independence as a guiding principle." Advertisement AdvertisementThe three agents — Michelle Ball, Jamie Garman and Blaire Toleman — said in a federal lawsuit filed in March that they were fired in a "retribution campaign" targeting them for their work on the investigation into Trump. The investigation the agents worked on culminated in an indictment from special counsel Jack Smith that accused Trump of scheming to overturn the 2020 election he lost to Democrat Joe Biden.