[goodtomato]

Cement backer board, mesh tape, insulation board (silver material with lettering), suspended ceiling grid and tile. Most parking garages are pre-fabricated, high strength concrete. Might find this material in the lobby but notice their is no sheetrock/ drywall in the debris. Photo is suspect to the eye of an individual who works with this material. But it is only a photo and no debris are visible on the weapon. Something that falls from above would cover what is below.

[r_barton]

Elevator lobby? Janitor closet? Electrical/data room?