Do not believe the assad regime did this. The only times gas has been used against anyone, it’s been the ‘freedom fighters’ and they are losing ground right now. Just like last time.
The Muslims extremists are well know for killing off their own or others if they think there is gain in doing so.
Obama has the US on the wrong side in every conflict in ME right now. The only thread that remains constant throughout the fabric of his ME policy are the Muslim Brotherhood and the Islamists. He is backing them in every conflict.