ALEPPO, Syria — Their names were Issa, Ahmed and Sheik Mahmoud Qasim. They were fathers and brothers. They were students, teachers and laborers.

And, last week, they were all killed by tank fire.

They are not alone. The Syrian conflict has now dragged on for 18 months and cost the lives of tens of thousands of people. The dead represent all kinds — civilians, rebel fighters, regime soldiers and officials, aid workers, activists, journalists.

More from GlobalPost: Complete coverage from Inside Syria

Headlines that track the numbers of dead are easy to pass over when they are so frequent. But sometimes a moment is captured that communicates the tragedy of events in a way that is impossible to ignore, or forget.

In this On Location video, GlobalPost senior correspondent Tracey Shelton tells the story of Issa, Ahmed and Qasim in the days before, and then at the very moment, they are killed in their back-alley post on the front lines of Aleppo, Syria.

GlobalPost originally published a series of seven stills taken from the raw video shot by Shelton. They depicted the four men at first laughing, then — in an instant — only one emerges from the cloud of smoke and debris. Now, more than a week later, the front line remains the same. New people have replaced the old as the battle continues with what seems like no end in sight.

GlobalPost’s On Location series brings you under-reported stories from around the world. The video series have won two Edward R. Murrow Awards, a Peabody Award, an Overseas Press Club award and multiple Best in Business awards from the Society of American Business Editors and Writers.