The F.B.I. has suspended an analyst on Kash Patel’s so-called enemies list after Mr. Patel told lawmakers that the bureau under his leadership would stay out of the political fray and not punish employees for partisan reasons.
Last week, the bureau placed the analyst, Brian Auten, on administrative leave, according to people familiar with the matter who spoke on the condition of anonymity because they feared retaliation. The reasons for the suspension remain unclear.
The F.B.I. declined to comment. A lawyer for Mr. Auten also declined to comment.
The suspension is likely to raise questions about whether the move was retaliatory, and about how closely Mr. Patel would stick to his promise, made during his confirmation hearing in January, that the agency would rise above partisanship despite pressure from President Trump’s allies to fire employees who took part in investigations that conservatives have condemned.
The suspension of Mr. Auten, who had already been disciplined and questioned in a criminal inquiry, will also likely intensify distrust of Mr. Patel among employees who have watched senior leaders forced out in recent months with no explanation.
Mr. Auten worked on two major investigations that angered Mr. Trump and Mr. Patel, including the F.B.I.’s investigation into Russian meddling during the 2016 presidential election. He was also involved in analyzing the information found on Hunter Biden’s laptop, a discovery that roiled the 2020 presidential campaign.
Mr. Patel has called the Russia investigation a hoax, and singled out Mr. Auten in his book, “Government Gangsters.” In the book, Mr. Patel claimed that the F.B.I. was trying to “hide and spin” what he called “the Biden family corruption” buried in the laptop, even as agents investigated the matter.
“Government Gangsters” also included a list of 60 names in an appendix called “Members of the Executive Branch Deep State.”
Mr. Auten was among the names listed in the appendix. At his confirmation hearing, Mr. Patel denied that it was an enemies list.
“It’s a total mischaracterization,” he told senators. He later added: “There will be no politicization at the F.B.I. There will be no retributive actions taken by any F.B.I., should I be confirmed as F.B.I. director.”
The suspension of Mr. Auten came after he and others had been disciplined for serious mistakes found in the F.B.I.’s applications for a secret surveillance warrant involving a former Trump campaign adviser.
Mr. Auten played an important role in unmasking the primary source behind a dossier of rumors and unproven assertions about Mr. Trump. The surveillance warrant applications relied in part on the dossier that Mr. Auten had examined extensively.
In the wake of the Russia investigation, known as Crossfire Hurricane, Mr. Auten had been suspended for 30 days, people said. After Mr. Patel became director, Mr. Auten was moved out of the counterintelligence division, one of the people said.
In his book, Mr. Patel denounced Mr. Auten.
“Yet just like his superiors, Auten has faced no real accountability in light of these findings,” he wrote. “The fact that Auten was not fired from the F.B.I. and prosecuted for his part in the Russia Gate conspiracy is a national embarrassment.”
The Justice Department’s inspector general found that F.B.I. officials had sufficient reason to open Crossfire Hurricane, and did not find evidence that the inquiry was politically motivated.
“We did not find documentary or testimonial evidence that political bias or improper motivation influenced” officials’ decision to open the investigation, the report said.
John H. Durham, the special counsel appointed by Mr. Trump to scrutinize the Russia investigation, said in his final report that “as an initial matter, there is no question that the F.B.I. had an affirmative obligation to closely examine” the tip that prompted the investigation.
But Mr. Durham accused the F.B.I. of “confirmation bias.”
In 2020, The New York Post reported on the laptop once used by Mr. Biden, writing that it contained damning evidence against him and his father, Joseph R. Biden Jr., who was running for president.
In his book, Mr. Patel criticized Mr. Auten’s role in the episode, claiming that he tried to “discredit any derogatory information about Hunter Biden by falsely claiming that none of it was true.”