No one can fart in Syria if not allowed by the Syrian Baath terrorist regime. For terrorists to mount such an attack without the knowledge and approval of the Syrian intelligence is not possible.
"Such an attack"? It doesn't sound half as well-thoughtout and executed as the plan two American high school knuckleheads pulled off in Columbine.
I'm not saying it couldn't have been staged, but I'd wait for some evidence first. Do you think the four dead people volunteered to die to put on a good show?