Narciso Contreras / Polaris A rebel fighter fires at enemy positions of Assad forces as skirmishes break out on the front lines in Aleppo, Syria, on April 9, 2013

The video starts out like so many of the dozens coming out of the war in Syria every day, with the camera hovering over the body of a dead Syrian soldier. But the next frame makes it clear why this video, smuggled out of the city of Homs and into Lebanon with a rebel fighter, and obtained by TIME in April, is particularly shocking. In the video a man who is believed to be a rebel commander named Khalid al-Hamad, who goes by the nom de guerre Abu Sakkar, bends over the government soldier, knife in hand. With his right hand he moves what appears to be the dead man’s heart onto a flat piece of wood or metal lying across the body. With his left hand he pulls what appears to be a lung across the open cavity in the man’s chest. According to two of Abu Sakkar’s fellow rebels, who said they were present at the scene, Abu Sakkar had cut the organs out of the man’s body. The man believed to be Abu Sakkar then works his knife through the flesh of the dead man’s torso before he stands to face the camera, holding an organ in each hand. “I swear we will eat from your hearts and livers, you dogs of Bashar,” he says, referring to supporters of Syrian President Bashar Assad. Off camera, a small crowd can be heard calling out “Allahu akbar” — God is great. Then the man raises one of the bloodied organs to his lips and starts to tear off a chunk with his teeth.

Two TIME reporters first saw the video in April in the presence of several of Abu Sakkar’s fighters and supporters, including his brother. They all said the video was authentic. We later obtained a copy. Since then TIME has been trying to ensure that the footage is not digitally manipulated in any way — a faked film like this would be powerful propaganda for the regime, which portrays the rebels as terrorists — and, as yet, TIME has not been able to confirm its integrity. Abu Sakkar has not commented on whether the man in the video is indeed him because he is currently fighting on the front lines in Syria, according to fighters under his command. The video became public on May 12 when it was posted online by a proregime group and is indeed now being used as propaganda by regime supporters (and has already been shared 1,115 times on Facebook and has over 46,000 views on YouTube). These 27 seconds of footage provide a glimpse at how brutal the Syrian war has become — and a startling example of how technology appears to be fueling that brutality.

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War is rarely anything but violent, but in Syria, where more than 70,000 civilians have been killed in the conflict since it started as a peaceful uprising inspired by the Arab Spring more than two years ago, the savagery has reached ghoulish proportions. And it seems that soldiers on both sides of the war are committing what appear to be crimes of war at least in part so that those acts can be viewed on the Internet. The ubiquity of camera phones and social media are enabling a mixture of propaganda, intimidation and boastful exhibitionism. In this, the first YouTube war, videos have driven the conflict even as they document its horrors.

Many videos from the Syrian battlefield, including the one that shows the man slicing out the dead soldier’s organs, also show the sectarian hatred that many fear is driving the war in Syria, especially the tension between the majority Sunni population and the minority Alawites. Assad is an Alawite; most rebels are Sunni. “Look at the heroes of Baba Amr,” shouts the man believed to be a rebel commander in the video, referring to a ferocious battle fought in 2012 between the rebels and regime forces near Homs, “slaughtering the Alawites and eating their hearts.” The anonymous blogger who posted the video on YouTube, attributing the video to al-Qaeda-affiliated Syrian rebel states: “These are the freedoms they want to import to our country.” The man in the video has been identified by another proregime group as Abu Sakkar, who commands the Al Farooq al-Mustakilla Brigade, a 60-man fighting force that is active in and around Homs, about 97 km north of Damascus and near the Lebanese border.

Videos like this prompt a troubling question: How do countries who want to support Syria’s rebels make sure they’re not unintentionally aiding rebels who might commit war crimes? Turkey, Saudi Arabia and Qatar are already providing the rebel forces with military aid, and the U.S. is helping with nonmilitary aid. There is an ongoing debate in Washington about whether the U.S. government should provide further aid to the rebels, possibly including weapons. Eating an enemy’s liver may be an extreme example of what appears to be a rebel atrocity, but there is enough documented evidence of extrajudicial killings, torture and desecration on the part of the rebels that it would be near impossible to know for certain who, exactly, are the “good” guys, says Peter Bouckaert, director of emergencies for the New York–based group Human Rights Watch. “In this context, where different rebel groups are fighting alongside each other, and sharing weapons, it’s difficult to control where the weapons end up. It is very likely that some of the weapons will end up in the hands of the likes of Abu Sakkar.”

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Brigadier General Salim Idris, head of the Syrian Military Council (SMC), which oversees — according to its leadership — about 90% of the rebel forces, says such violence is unacceptable, and that no soldier under the council’s command would be allowed to get away with such actions. “Look, it is very clear that these kinds of behaviors, this cutting of bodies, is not allowed. If there is evidence that fighters from the FSA are doing something against human rights or international law, they will be brought before the court,” says Idris, referring to the Free Syrian Army, an umbrella name for the anarchic consortium of defected government soldiers, volunteers, jihadists and opportunists that make up most of the opposition fighting force, and nominally pledge allegiance to the SMC. Idris, who has not seen the video, but was told of its existence, questions the value of videos as proof, pointing out that they can be digitally manipulated. Furthermore, he maintains that the SMC has a watertight command-and-control structure in place that prevents these kinds of atrocities. He suggests that if they are happening, they are being perpetrated by the fighting groups not under his jurisdiction. Then he lashed out against Western journalists who focused on the human-rights abuses of the rebels, when “the regime is massacring women and children with knives. Where is international law when it comes to 200,000 martyrs and millions of refugees?”

The video featuring the man believed to be Abu Sakkar is symptomatic of the blend of brutality and technology on the Syrian battlefield. According to several rebels interviewed by TIME, fighters from both sides no longer simply brag about their exploits on the battlefield; they film them and share them, competing in gruesome games of one-upmanship. This trading in trophy atrocities, played up for the camera and passed from phone to phone, has a desensitizing effect, says Rami Abdel Rahman of the Syrian Observatory for Human Rights, a pro-opposition U.K.-based organization that tracks fatalities and human-rights abuses in Syria. When a 13-year-old boy is filmed beheading a man and when footage of rape, torture and amputations are passed like trading cards, it escalates the cycle of honor-driven revenge, as each atrocity, so publicly shared, demands a response from the opposing side, according to Nadim Houry of Human Rights Watch. “When people see these acts of brutality and mutilation, it leaves deep scars, and there will be a temptation to replicate it in revenge,” says Bouckaert. “An eye for an eye, and a tooth for a tooth. Quite a few fighters in Syria interpret that literally.”

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Rahman says violent videos are showing up with increasing frequency. “I’ve seen hundreds of videos like that from both sides,” he says. “They cut off limbs and heads. They cut out hearts and livers, ears and tongues. They cut off private parts and put them places. It’s abnormal. It’s inhuman what is happening.”

The apparent rise of such incidents — or at least their documentation — is an indication that the Syrian conflict is going in a very dark direction. And it could get worse. Many Syria scholars say the regime — and the war — could last for years.

There are no good options for the international community. Western intervention on behalf of the rebels could exacerbate sectarian tensions. Foreign boots on the ground could incite an Iranian response in support of the regime, which it backs, sparking a wider regional proxy war. Al-Qaeda leader Ayman al-Zawahiri has encouraged all jihadists to join in the fight against the Syrian regime; further instability, with its rich recruitment pool and increased lawlessness, is the terrorist group’s ideal incubator. And as more horrific videos emerge, the rebels may find it harder and harder to persuade the international community that they represent the best bet for a country descending ever further into chaos.

— With reporting by Rami Aysha / Tripoli