While the U.S. government was negotiating with Taliban representatives on the controversial prisoner swap that set Sgt. Bowe Bergdahl free, Bergdahl's family opened up a separate channel to the Taliban to try to buy his freedom with cash, according to two sources with knowledge of the case.

This channel of negotiations has not been previously reported. It was focused on winning Bergdahl's freedom with a $10 million ransom to be paid by private sources, not U.S. government money, the sources say. These talks started in 2012 and continued until May 2014.

The revelation of this second set of negotiations underscores two points: Bergdahl might have been freed without the release of the five Taliban from the Guantanamo Bay detention camp, and the Taliban are still driven heavily by the need for cash.