Abu Mohammed still remembers the smell. It usually came at dawn, as the mosques sounded the first call to prayer. By the time he sat down for breakfast, it would fill the air around his home in Tadamon, a working-class district in the south-east of Damascus. The smell was hard to define. Whenever he noticed it, Abu Mohammed felt on edge. He had his suspicions about what it might be, but like so many Syrians who lived under the dictatorship of Bashar al-Assad, he knew to keep such thoughts to himself.

Abu Mohammed, a retired engineer who asked to be identified only by his nickname, first noticed the smell in the winter of 2012, nearly two years after the start of the uprising against Assad. At the time, he was living in a modest flat in the heart of Tadamon with his wife and their five children. The house stood just off a busy road named Daboul Street. Before the fighting started, Abu Mohammed enjoyed sitting on his balcony after work, sipping his tea as he watched the yellow minicabs and honking motorbikes compete for space in the streets below.

But by the time the smell became noticeable, these streets were largely deserted. The Assad regime had rolled out a network of checkpoints across the neighbourhood in an attempt to quell protests after the 2011 uprising. Hiding behind a curtain so he wouldn’t be seen, Abu Mohammed watched soldiers patrolling the streets. He also noticed white minibuses driving up and down Daboul Street. Whenever the minibuses passed by, he would hear gunfire later that day. Then, overnight, that same smell. One of his daughters, who was in her early teens at the time, remembers it, too. “It smelt like burning hair,” she recalled. “Or like a piece of meat that has been left in a pan until it melts.”

Nearly a decade later, in April 2022, the Guardian published a video that revealed the source of the smell. The footage carried a date tag from April 2013 and was geolocated to Tadamon. It showed two men in military fatigues next to a white minibus. One of the soldiers could be seen pulling a civilian, blindfolded, out of the van and dragging him towards a large pit filled with bodies and car tyres. The other stood by the edge of the pit with an assault rifle. Calmly, he pushed his victim into the pit and executed him as he fell on to the other victims. They did this time after time. When 41 people lay dead, the shooter took a jerrycan of fuel, poured it over the tyres and the bodies, and set the pit on fire with a burning rag attached to a wooden stick.

The footage was part of a collection of videos leaked by a source inside Syria and obtained by two genocide scholars in Amsterdam, Annsar Shahhoud and Uğur Ümit Üngör. The researchers shared a selection of the material with the Guardian and submitted the rest to European war crime prosecutors. In total, the videos document the killing of 288 civilians by Assad’s forces, the academics concluded, including seven women and 12 children.

One of the scholars, Shahhoud, managed to identify the main shooter seen in the video. His name is Amjad Youssef and he served as an officer in Branch 227 of the Assad regime’s military intelligence. Using a fake Facebook account in which she posed as a regime loyalist, Shahhoud sent him a friend request, gained his trust over several phone calls, and lured him into confessing his crimes. When she confronted him with the video, he replied: “I am proud of my deeds.”

As long as Assad was still in power, no one in Tadamon dared to mention the video in public. According to Abu Mohammed, Youssef remained in the neighbourhood after the video was published, as if nothing had happened. “He would just drive up and down the street on his motorbike. No one would say anything.”

But now that the dictator is gone, the people of Tadamon are breaking their silence. As they have begun to share their stories, it is becoming clear that the atrocities in the neighbourhood were far worse than initially reported – and involved many more perpetrators besides Youssef.

Between March and August this year, I visited Tadamon multiple times and spoke with more than 20 residents. Abu Mohammed, a short elderly man with a soft smile, was one of the first people I met. As soon as he noticed me in the street, he grabbed my arm. “I stayed here throughout the war,” he said.