Bias Played Part in F.B.I.s Jan. 6 Failure, Documents Suggest

The F.B.I. appeared to be blinded by a lack of imagination, a narrow focus on lone wolf offenders and a misguided belief that the threat from the far left was as great as that from the far right, new congressional documents show.

WASHINGTON Days before the end of the 2020 presidential race, a team of F.B.I. analysts tried to game out the worst potential outcomes of a disputed election.

But of all the scenarios they envisioned, the one they never thought of was the one that came to pass: a violent mob mobilizing in support of former President Donald J. Trump.

The teams work, which has never been reported, is just the latest example of how the Federal Bureau of Investigation was unable to predict or prevent the chaos that erupted at the Capitol on Jan. 6, 2021. Apparently blinded by a narrow focus on lone wolf offenders and a misguided belief that the threat from the far left was as great as that from the far right, the analysis and other new documents suggest, officials at the bureau did not anticipate or adequately prepare for the attack.