Federal investigators have zeroed in on flaws in the pool deck as the preliminary cause of the 2021 collapse of a 12-story Florida beachfront condominium that killed 98 people.

The National Institute of Standards and Technology said in a report Wednesday that the Champlain Towers South pool deck began falling down at least seven minutes before the tower, suggesting the pool dragged the building down with it.

Glenn Bell, co-lead investigator at NIST, said detailed analysis and computer simulations “indicate that it is more likely that the failure started in a pool deck slab-column connection.”

Most residents were asleep when the building in Surfside, Florida, collapsed into a huge pile of rubble at 1:22 a.m. on June 24, 2021. As the investigation continued, a Miami judge approved a more than $1 billion settlement for personal injury and wrongful death claims from the disaster.

Surfside is located a few miles north of Miami. NIST said its final conclusions on the collapse will be released in spring or summer 2026.

The preliminary findings also showed the “building was in distress in the weeks before the collapse.” Among the indicators of deeper-seated problems were a door that dislodged from its frame, cracks in a wall where heavy planters were located and a gate that shifted and became jammed shut.

The day before the disaster, the NIST report says, water was leaking from a ceiling in the parking garage that had experienced numerous cracks and the flow “dramatically increased in the hours before the collapse.”

NIST previously said the construction flaws that led to the collapse were present from the time the 40-year-old structure was built. The findings of the Champlain Towers investigation will improve building safety, both new construction and repairs for older structures, said investigative lead Judith Mitrani-Reiser.

“This tragic event has revealed flaws in our systems, and quality is at the heart of it,” she said.

After the collapse, state legislators enacted a law in 2022 requiring condo associations to have sufficient reserves to cover major repairs. Some residents were caught off guard by hefty fees imposed to cover years of deferred maintenance expenses required to bring their buildings into compliance with the law’s standards. That led to another law providing condo associations and residents more flexibility in handling the costs.

Meanwhile, a luxury condo building called the Delmore is being constructed on the collapse site, which was purchased at auction by Dubai-based DAMAC International for $120 million. The starting price is $15 million each for the new condos, expected to be completed by 2029.