Manhattan DA investigating parking garage collapse that killed 1

The Manhattan district attorney's office will investigate the partial collapse of a parking garage that killed one and injured five others, a spokeswoman for the office confirmed Wednesday.

More than 50 cars were parked on the roof of the three-story Lower Manhattan building when it collapsed Tuesday afternoon, sending cars plummeting and killing one worker whose body remains trapped in the debris, officials said Wednesday.

The New York City Fire Department is slowly and methodically taking down the building. Gas tanks and electric vehicles in the debris are complicating the deconstruction process.

"This is an incredibly complex operation," emergency management commissioner Zach Iscol said during a press briefing Wednesday. "The building is not structurally sound."

The city is working to "safely demolish" the building while also removing the vehicles, he said.

The NYPD identified the 59-year-old victim on Thursday as Willis Moore of Queens.

New York City Mayor Eric Adams confirmed Wednesday that the deceased garage worker also remained in the collapsed building. The man was a manager of the garage, sources said.

Four workers were treated at local hospitals following the collapse, while a fifth refused medical treatment, officials said. The New York Fire Department said it appears most if not all of the patients have since been released.

Department of Buildings acting Commissioner Kazimir Vilenchik said the building "pancaked," and that the ceiling collapsed "all the way to the cellar floor."

Firefighters went inside the building to search for victims but it was continuing to collapse so they evacuated. A robotic dog and a drone were brought in to continue to search the building. Officials believe that everyone is accounted for and there is no reason to believe this is anything but a structural collapse.

The exact cause of the collapse remains under investigation.

"There's a thorough investigation that is going to happen with this building. And we're going to learn from it," Adams said.

A focus of the investigation is the weight of the vehicles parked on the roof and the age of the building, which was built in 1925.

The parking garage, which is owned by 57 Ann Street Realty Association, currently has four active violations, according to records from the New York City Department of Buildings.

The violations that remain open were recorded between 2003 and 2013.

One of the four violations still open is from Nov. 25, 2003, and has a severity status listed as "hazardous." In the violation details, the department recorded the discovery of cracks in the concrete on the first floor, calling the concrete "defective."

The company did not immediately respond to a voicemail seeking comment.

The parking garage tenant, Enterprise Ann Parking LLC, said in a statement Wednesday: "This is a tragic event. We are devastated at the loss of one of our long-time employees and our thoughts are with his family and those who were injured in the accident. We thank all of the first responders who quickly attended to those who were impacted and appreciate their courageous work."

"We are fully cooperating with city agencies and other authorities as they investigate this incident," it added.

ABC News' Aaron Katersky, Mark Crudele and Victoria Arancio contributed to this report.