The Civic Center and UN Plaza were cleared after a man with a handgun was spotted, but no shots were fired.
"It does not make sense to us how this incident resulted in the loss of life," the brother of Keith Lamont Scott said after new videos were released.
The reversal comes a day after NBC News obtained cellphone video taken by Scott's wife showing his fatal encounter with police Tuesday.
The floor collapsed as the firefighters entered the building in Wilmington, Del. Two other firefighters were injured and are in critical condition.
Stacey Konwiser, who was mauled to death by a tiger in April, screamed for help into her radio before the deadly encounter, an autopsy report says.