Bloggers Lady Liberty and Doug Ross have done some digging into the social media history of Robert Bergdahl, and found what looks like evidence he has had a disturbing cozy online relationship. As Doug Ross summarizes the work begun by Lady Liberty:

On Google Plus, Robert Bergdahl's contacts include one "Anissa bint Yusuf Zaid Ibn Youssef."

And just who is Anissa? From this link (translated), she would seem to be a 10-year member of an Al Qaeda technology support team.

I thank Allah (Subhana Wa'a Ta'laah) for guiding me on the path of truth, righteousness and justice, which is the Path of Jihad. Agradezdo my beloved brothers and sisters of the Scientific and Technological Committee of Al 'Qaida and TTP, as also to the various centers Translations of the Jihad, Al Al'Qaida General Command and the Taliban who have allowed me to develop and exhibit my work over 10 years.

Based on Bergdahl’s YouTube Channel, there is certainly the possibility that the elder Bergdahl converted to islam, though no conclusions can be drawn.

But Doug correctly notes:

It's a pity the NSA -- with its massive surveillance program, unlawfully monitoring the conversations of every American citizen -- didn't let us know these salient details ahead of time.

One has to wonder if, the NSA was even interested, as with the Tsarnaev brothers, whose activities should have triggered some alarms.