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.