I find it odd how we got down to one suspect. Consider:

-witness reports clearly spoke about two attackers, and 

-two suspects were arrested and identified, and

-the mosque said it knew neither individual (including the one arrested at the mosque), and

-police were quite convinced there was no further threat after the two arrests.

So who is Mohamed Khadir (or Belkhadir, or El Khadir) that police were able to release him so quickly?