The kidnappers in fact had ties to the so-called "moderate" rebels and not the Assad regime.
NBC network concerns at the time, were that it might not have been Assad, but they chose to set that aside before further investigation, for the PC anti-Assad, Obama pro-rebel backed spin.
http://money.cnn.com/video/media/2015/04/16/richard-engel-nbc-news.cnnmoney/index.html?iid=ob_marketpg_video&iid=obnetwork