Who used Chemical weapons in Syria?

Syria is currently experiencing civil war and political instability. After years of civil war the country is divided by the rebels and the government. Although the United States has not been directly involved in the violence first hand thus far in the conflict. This is being reconsidered after it has been confirmed that a chemical gas sarin was used as a weapon in the country. This attack killed up to 1400 reports say, including women and children. The big question is not whether the use of this gas as a weapon is crime, of course it is. The question is who used the gas on who?  After the first reports Obama appears to be in the opinion that the Assad regime is to blame for the devastating gas, while Putin was reported to be convinced the rebels were to blame. Who is right? "We know that Assad's chemical weapons personnel prepared for an attack near an area where they mix sarin gas,” President Barack Obama said in an address to the nation on September 10." "No one doubts that poison gas was used in Syria,” he wrote. “But there is every reason to believe it was used not by the Syrian Army, but by opposition forces, to provoke intervention by their powerful foreign patrons, who would be siding with the fundamentalists." 

http://worldnews.nbcnews.com/_news/2013/09/16/20524937-un-report-confirms-chemical-weapons-use-in-syria?lite