The next day on 30 August 2013 the Obama White House officially releases a statement that based upon U.S. Intelligence it has "high confidence" that the Syrian Assad Shi'a Muslim government did the chemical attack, as I linked to earlier: https://obamawhitehouse.archives.gov/the-press-office/2013/08/30/government-asseSsment-syrian-government-s-use-chemical-weapons-august-21