Erin Burnett OutFront -

Friend: Bowe Bergdahl voluntarily left his army base

Army Sergeant Bowe Bergdahl, was freed in a prisoner swap after nearly five years in captivity with the Taliban. For the first time, Bergdahl's friend is now speaking out, saying he believes Bergdahl walked away from his post in Afghanistan in 2009.

It's been four months since Bergdahl was freed and now CNN is learning new details about what he's doing and why he hasn't spoken to his own parents for so long.

CNN's Ed Lavandera has this exclusive OutFront investigation.