Notice also the attached two story portion still standing? It was a day care center for children.
When the trusses failed, classic V-pattern collapses were seen down both walls.
Notice how the trusses completely came apart at the gusset plates. And this was with no fire and no impact loads, just a long, hot summer combined with suspect construction methods.
Kudos to E22C, E66C and Q35C for their work at the scene and for the photos, many more of which can be seen at G:\Operations\Batt05\C_SHIFT05\collapse 0811. And thanks to Ed Services who continue to turn out relevant, timely continuing education.
(Editor's Note: Special thanks to DC David Bailey for all this great info!)