It’s addressed at least twice in the piece, once in the CNN interview where Long describes picking up the spray can off the ground, and even here, where I transcribe Long’s quote: “when he shot the gun that’s when I used the spray paint and the lighter to make the flames.”

And if you watch the embedded video of the full sequence, you can see at the start that Long is spraying paint — a dusty white cloud of it, in the face of Preston (and others).