In the months after Sgt. Bowe Bergdahl was freed from Taliban captivity, senior Army officials responsible for determining why he walked off his outpost and for recommending what the consequences should be struck a far milder and more sympathetic tone than Army commanders who are now pursuing charges that could send him to prison for life, new documents show.

The documents, which have not previously been disclosed, indicate that the Army’s 22-member investigative team, which spent two months interviewing scores of witnesses and compiled the report that formed the initial basis for prosecuting Sergeant Bergdahl, never proposed that he could be tried on the most serious charge he now faces: endangering the troops sent to search for him.

This dissonance has led members of the sergeant’s defense team to question whether the tougher line reflected improper influence from higher levels of the military or political considerations as top Republicans in Congress and on the presidential campaign trail declared the sergeant guilty and demanded he face stiff punishment.

The documents include a 371-page transcript of Sergeant Bergdahl’s interview in August 2014 with Maj. Gen. Kenneth R. Dahl, who headed the Army’s investigation. The transcript provides the most complete account yet of his disappearance from a remote base in eastern Afghanistan in June 2009, which prompted a huge manhunt.