In a huge blow to President Bashar al-Assad’s forces, various rebel units under the Free Syrian Army managed to disperse government troops from three checkpoints in the northwest province of Idlib on Friday.

The battle for the town of Saraqib, which lies thirty miles southwest of Aleppo, has been an especially brutal fight between loyalist and rebel forces in the last week. With the defeat of Syrian troops there and the scattering of their units to other parts of the country, the Free Syrian Army has stricken a deep setback to the regime’s defensive positions.

The fact that Saraqib is strategically located between two key transportation arteries will make it extraordinarily difficult for the regime to send reinforcements to their troops in Aleppo, where the regime’s army has been locked in major urban warfare for the past four months.

But any jubilation that the rebels felt after dislodging regime forces was quickly overshadowed by horrific images of them taking justice into their own hands. An amateur video that was released on public forums immediately after the battle depicted a large group of rebels beating, kicking and eventually executing a small cadre of captured government soldiers. The video is graphic not only due to the killings but because the captured men appeared terrified and were pleading for their lives. Their pleas were ignored. All ten soldiers were murdered in a hail of gunfire.

Rupert Colville, the spokesperson for the United Nations High Commissioner on Human Rights, quickly spoke to reporters after the incident to make the organization’s disgust known. “Unfortunately, this could be the latest in a string of documented summary executions by opposition factions as well as by government forces and groups affiliated with them,” Rupert said. “The allegations are that these were soldiers who were no longer combatants and therefore, at this point, it looks very like a war crime.”

Indeed, this wasn’t the first time that rebels fighters have been accused of war crimes or crimes against humanity. Another particularly violent episode was recorded last August which consisted of an FSA brigade killing fifteen members of a prominent Syrian clan that was reportedly helping Bashar al-Assad quash protests in Aleppo. The men were told to say their names to the camera before being ushered outside and killed in a mass execution. Another video released shortly after showed rebels tossing the bodies of dead Syrian soldiers from a ceiling after a police station was captured.

Rebel commanders have tried to reduce the damage, telling CNN that they in no way condone or accept the type of behavior that was recorded in the video. One spokesman blamed extremist elements for the crime, adding that those who engaged in the killing would be detained and tried by the opposition if caught.

Whether anyone will be held accountable is exceedingly unlikely in a war that has claimed the lives of over 36,000 Syrians and resulted in the displacement of more than three million. While the Syrian government appears to be perpetrating most of the atrocities on the ground and through the air, videos like the one released on Friday show that rebels of all stripes are copying such heartless tactics.

This is a terrible development, not only for the sake of human rights law but also for the opposition’s campaign to elicit weapons and support from abroad. Extrajudicial killings, even if carried out by a small band of anti-Assad fighters, hurts the credibility of the entire movement in the eyes of the Western world.

Denouncing atrocities of all kinds is fine and talking of prosecution is even better but holding people accountable for war crimes will be extremely difficult in a conflict where both sides view the other as the offspring of the devil.