that led to growing alarm about bergdahl's medical condition and safety, a senior u.s. official tells cnn. defense secretary chuck hagel is aware of the details in that classified file. >> let's get the facts but let's first focus on getting sergeant bergdahl well. >> reporter: hagel is saying little else. >> the army will conduct a comprehensive review of all the circumstances regarding sergeant bergdahl's disappearance. and i think i would leave it there. >> reporter: cnn has learned that an initial fact-finding investigation at the time of bergdahl's disappearance included statements from other troops that he had left the base on other occasions. according to a u.s. official briefed on the findings. in that fact-finding report officials say bergdahl's commanders called him a good