We're getting new information this afternoon about a purported letter left behind by Sgt. Bowe Bergdahl before he walked away from his base in Afghanistan five years ago. After a prisoner swap in which Bergdahl was handed over in exchange for five Taliban leaders, some of his fellow soldiers have said in recent days that Bergdahl deserted the unit.

Sources who had debriefed two former members of Bergdahl’s unit told Fox News Bergdahl left behind a note the night he left base in which he expressed disillusionment with the Army and being an American and suggested that he wanted to renounce his American citizenship and go find the Taliban. U.S. military officials would not confirm the existence of the letter, but if it does exist, it would likely be part of the original file on the investigation into Bergdahl’s disappearance.

The letter is presumed to be part of classified documents contained in the investigation into Bergdahl's disappearance. The Pentagon has said it will not release the contents of the probe at this time.

In the video above, watch Jennifer Griffin's report from Happening Now.

Meantime, chairman of the Joint Chiefs of Staff Gen. Martin Dempsey cautioned Americans not to rush to judgment on the exchange.

“The questions about this particular soldier’s conduct are separate from our effort to recover any U.S. service member in enemy captivity,” Dempsey wrote on Facebook this morning. “This was likely the last, best opportunity to free him. As for the circumstances of his capture, when he is able to provide them, we’ll learn the facts. Like any American, he is innocent until proven guilty. Our Army’s leaders will not look away from misconduct if it occurred.”

Earlier today on Fox and Friends, the parents of a fallen U.S. Army officer said they have learned in recent days that their son was killed during an operation to find Bergdahl. They accused the U.S. government of covering up that fact, telling them that their son was killed while hunting for a Taliban commander.

The Outnumbered panel, including #oneluckyguy Lou Dobbs, weighed in this afternoon on the latest in the Bergdahl case. Watch the discussion in the video below.

See the latest on the Bergdahl swap from Fox News:

Soldier's Parents: Son Died Looking for Bergdahl, Gov't Covered It Up

McCain to Hemmer: 'Obama Has Restored Mullah Omar's Cabinet'

Dick Cheney: ‘Distinct Possibility They’ll Go Back in the Battle’

Talking Points: O'Reilly Reacts to Bergdahl Exchange