It increasingly seems probable that some folks suffocated or were overcome with smoke inhalation and hypoxia (oxygen deprivation) when buildings, tunnels and underground bunkers collapsed into clouds of dust during the final battle for Douma last Saturday.
Then the desperate remnant of the jihadist Army of Islam (Jaysh al-Islam) holed up there piled the bodies in a basement, spread shaving cream on their lips and proceeded to videotape furiously. Thereafter, they charged into a nearby hospital (which was treating hypoxia victims) with their video cameras in hand, yelling "chemical attack" while water-hosing one and all, thereby setting off the pandemonium seen on social media around the world.
We haven't gotten to Douma yet to check out this contra-narrative, but an intrepid young reporter named Pearson Sharp did. Along with his camera crew, he visited the site of the attack, the hospital and the nearby rebel weapons dump----and interviewed dozens of people in the immediate vicinity.