Federal investigators released the results of their investigation into what caused the deadly 2021 collapse of the Champlain Towers South condo in Miami that killed 98 people.

Five years after the disaster, the National Institute of Standards and Technology blamed the failure of two garage column connections beneath the pool deck. The critical moment occurred roughly three weeks before the actual collapse, when the connections between the concrete slabs and columns failed, according to the investigation, crediting the findings to an “extensive technical investigation.” This caused “cracks to grow and loads to redistribute in the pool deck over the next three weeks,” NIST said.