Sarin gas samples

Secretary of State Kerry has been on national TV assuring the nation the government has obtained hair and blood samples that prove Syria's Asad used sarin gas on his own people.

I question where did the samples come from?  Who gathered the samples?  Who gave the samples to the U.S. government authorities?  I recall my early days working in the oil patch on a drill rig.  When a new eager beaver geologist showed up at the drill site we, the roughnecks, would throw extraneous stuff into the mud stream so when it went through the shale shaker the geologist would find it and get all excited about the unusual samples he was catching.  Of course, he became the butt of the joke.  It was a kind of initiation for the new guy.

So, I say question the source of the samples and who gathered them before going on national TV espousing the authenticity of the sarin gas samples.