The F.B.I.’s decision in 2010 to keep the interview summaries secret led some critics to question the quality of the evidence against Mr. Awlaki. The 200 pages of redacted documents released to The Times this week, on the order of a federal judge, suggest that the Obama administration had ample firsthand testimony from Mr. Abdulmutallab that the cleric oversaw his training and conceived the plot…

He advised Mr. Abdulmutallab to blur his trail by traveling from Yemen to an African country before booking the flight on which he intended to detonate his bomb. The choices of exact destination and timing were left up to Mr. Abdulmutallab, who said Detroit and Dec. 25 were random decisions dictated by ticket prices and flight schedules.

Mr. Awlaki offered a final reminder: “Wait until you are in the U.S., then bring the plane down.”

With this instruction in mind, Mr. Abdulmutallab told the F.B.I., he followed the progress of Northwest Airlines Flight 253 on the seat-back screen from Amsterdam into Canada, then waited as it approached the United States border. He went to the airliner’s bathroom to make final preparations for his attack and considered trying to set off the bomb there. But to be certain he was over American soil, he returned to his seat to check the map before pushing the plunger under his clothing to mix the chemicals and ignite the explosives.