A report compiled by three international war crimes prosecutors claims that the Syrian government is behind the "systemic killing" of approximately 11,000 detainees between March 2011 and August 2013.
The Guardian, which obtained access to the report, says that the source of the report's claims is a military police photographer who secretly worked with a Syrian rebel group before defecting and fleeing the country. In the process, the defector smuggled the images of "killed detainees" out of the country on memory sticks.
The defector, identified in the report as Caesar, does not claim to have witnessed executions or torture himself. However, he describes the bodies of detainees, mostly young men, as being emaciated, blood-stained, and in some cases bearing signs of strangulation or electrocution.