" 'Our investigators have been in neighboring countries interviewing victims, doctors and field hospitals and, according to their report of last week which I have seen, there are strong, concrete suspicions but not yet incontrovertible proof of the use of sarin gas, from the way the victims were treated,' Carla Del Ponte, a member of the UN commission told Swiss-Italian television.
'This was use on the part of the opposition, the rebels, not by the government authorities,' she added.
According to the commission, they have yet to see evidence that Assad's forces used the chemical, despite accusations made against the regime by the U.S. and NATO governments."
http://www.examiner.com/article/un-commission-claims-to-have-evidence-rebels-launched-chemical-attack-syria