In this picture taken on Sunday, June 24, 2012, a Syrian rebel fires his weapon during clashes with the Syrian forces troops, at Saraqeb town, in the northern province of Idlib, Syria.

In this picture taken on Sunday, June 24, 2012, a Syrian rebel fires his weapon during clashes with the Syrian forces troops, at Saraqeb town, in the northern province of Idlib, Syria. Investigators say they have concluded that Syrian government troops could be behind the killing of more than 100 civilians in the village of Houla last month. The findings, which were presented to the U.N.'s top human rights body, could lay some of the groundwork for prosecuting alleged crimes against humanity or war crimes in Syria. (AP Photo/Fadi Zaidan)