As if to punctuate a recent report by Amnesty International detailing the human rights violations committed by several US backed rebel factions in Syria, the Nour al-Din al-Zinki Movement, one of the US supported factions, has been caught on film beheading a young Palestinian boy.

The video shows fighters from the rebel group with a boy who is described as 13-years-old, presenting it as capturing “an Assad soldier.” A second video was released showing them cutting the same boy’s head off in the back of a truck.

The incident took place in Hanadarat, where Syrian troops have been fighting against a coalition of US-backed rebels, which includes the Nour al-Din al-Zinki as well as the Free Syrian Army. The Free Syrian Army was critical of the killing, saying they intend to hold those responsible accountable.

In practice, that’s rarely happened, with Amnesty’s report underscoring how common torture and summary executions actually are among all combatants in Syria. Today’s incident wasn’t out of the ordinary, and happened to become news because the video came out.