Brooklyn building collapse investigation focuses on structure's history, nearby construction

NEW YORK -- City records show demolition and construction work had been going on for months next to a 96-year-old Brooklyn building at 1321 Flatbush Ave. that collapsed Wednesday night, killing at least four people and injuring at least 17 others.

Investigators are now examining the debris left behind to determine what caused the collapse, which shocked residents and left city leaders with unanswered questions.

Google Maps imagery shows the commercial building that once stood at the adjacent construction site. Compared with chopper video from Wednesday, the neighboring building is gone, and rubble fills the construction site next door.

Construction safety expert Glenn Corbett of John Jay College, who has not investigated the site, said excavation work near older structures can present stability concerns.

"When you go and dig next to these kind of buildings, there's always an issue of stability," Corbett said.

Corbett said retaining walls, or shores, commonly used to support the perimeter of construction pits, can become a point of concern during investigations.

"What was it not built correctly with the size of the members, the wood panels not large enough was the... if there was steel involved, which I believe there was, was that not, was that not up to speed as far as what's required?" Corbett said.

According to Department of Buildings records, one summons was issued in April for the construction site along Bedford Avenue. A stop-work order was allegedly violated but was later resolved.

Blueprints show a mixed-use building was under construction at the site, with plans for retail space, medical services and residential apartments.

WABC found no building violations for the site of the building that collapsed. Corbett said it is important for New York City to understand the cause of the deadly incident.

"They've got to find out why did that happen? And do we need to change the rules?" Corbett said.

WABC called the number listed for the contractor who received the summons in April. The contractor said the company carried out the demolition work but had left the job site by late April or early May. He said he was not aware of any existing condition of the shores.

The investigation into the cause of the collapse remains ongoing.