(CNN) As rescuers sift through the rubble of a South Florida condo building, investigators have been searching for answers as to what triggered the collapse.
Officials have confirmed 22 deaths, and dozens more remain unaccounted for.
As families mourn and worry for their loved ones, residents and officials are criticizing the management of the building, saying more should have been done to prevent the tower from crashing down in the middle of the night last week.
Officials say they still haven't found what triggered the collapse, but engineers have told CNN it is likely the product of multiple factors rather than a single failing.
From an early construction halt to assurances that the building was fine, here is what we know so far about the damage and repairs to the building.
Before Champlain Towers South and one of its sister buildings opened, there was controversy around their construction, which violated local regulations, documents show.
"You are instructed to immediately cease any further construction on any penthouses at either of the Champlain Towers buildings," Surfside's acting town manager at the time, George Curti, told the tower's contractor in a December 2, 1980, letter.
Surfside's attorney had determined the penthouse violated town code, Curti wrote.
The following week, the Town Council granted an exception, allowing the penthouse construction to go forward, Curti wrote in a follow-up letter.
The issue was over the buildings' height: The penthouses had not been in the original plans and they brought both buildings above the town's 12-story height limit, The Wall Street Journal reported.
Maryland-based Morabito Consultants performed a structural analysis as part of Champlain Towers South's 40-year recertification effort -- a stringent process for updates and improvements enacted after Hurricane Andrew in 1992.
The structural field survey highlighted "abundant cracking and spalling" in concrete columns and walls, "exposed, deteriorating rebar" and failing waterproofing beneath the pool deck and entrance drive that was causing "major structural damage" to the concrete structural slab. It warned of rapid deterioration if it wasn't promptly replaced, according to the report.
"Morabito Consultants provided the Champlain Towers South Condominium Association with detailed findings and recommendations nearly three years ago regarding the structural repairs that were needed on the building to ensure the safety of the residents and the public," a Morabito statement said this week.
Then-Surfside building official Rosendo Prieto appeared not to stress the damage in a 2018 meeting, according to the meeting's minutes.
Noting he had reviewed the Morabito report, Prieto said the "necessary data" had been collected for the recertification process "and it appears the building is in very good shape," the minutes say.
Prieto no long works for Surfside. He is on a leave of absence with his current employer, CAP Government, Inc., according to the city of Doral, which said it is reviewing eight projects to which CAP Government assigned Prieto. He has not responded to CNN's requests for comment.
Surfside Commissioner Eliana Salzhauer doesn't believe the condo association responded adequately to the Morabito report, she said. The association should have made concerns more clear to residents, she added.
"In hindsight, they should have made more noise," she said. "They had a report. It said very clearly, 'Your building is in bad shape.'"
The condo association declined to comment on specifics, but the association's surviving members released a statement Friday, saying, "We know that answers will take time as part of a comprehensive investigation and we will continue to work with city, state, local, and federal officials in their rescue efforts, and to understand the causes of this tragedy."
A nine-page October letter from Morabito Consultants to association board president Jean Wodnicki provided the scope of some of the damage in the pool area and the work being done to address it.
Loose concrete around the perimeter of the pool pump room that showed signs of cracking, spalling and deterioration -- presenting a "fall hazard" -- had been removed, the summary said.
Morabito Consultants noted it could not perform all of the repair work in the pool area because of concerns about stability. The firm also needed access to the inside of the pool but had been told it needed to remain open during the work, the letter delivered last year said.
There is currently no indication that the concrete deterioration was a contributing factor to the collapse, but it does highlight major repair work needed at the Champlain Towers South condominium complex.
Engineers and experts compared a 2021 photo of concrete in the pool equipment room, published in the Miami Herald, to a 2018 photo of the same area and told CNN the condition appears worse in the more recent picture. The cause of the deterioration is not clear.
The equipment room is in the same area -- below the pool deck -- where Morabito had warned in 2018 of failed waterproofing and concrete deterioration.
The progression seen in the crack portrayed in the two images could be the result of the waterproofing problem, or concrete could have fallen off in the three years following the 2018 photo, revealing a deeper fissure, experts told CNN.
"Once deterioration like this starts, it's insidious. It just continues. Unless you do something about it, the whole thing is going to fall apart. All of the concrete is going to fall apart," said Matthys Levy, a consulting engineer and author of "Why Buildings Fall Down."
While stopping short of saying that the deterioration in the pool area could have caused the building's collapse, many engineers said the damage was likely indicative of poor maintenance throughout the building.
"It just generally shows what a crappy condition the concrete was in. You can draw whatever conclusions you want -- that maybe the rest of the concrete was just as bad," Levy said.
A letter sent earlier this year to the building residents said the "exponential" concrete deterioration had taken place between 2018 and 2021.
"The concrete deterioration is accelerating," Wodnicki wrote. "The observable damage such as in the garage has gotten significantly worse since the initial (2018) inspection."
While the estimate for repairs stood at roughly $9 million in 2018, the price had risen to about $15 million by April, the letter noted.
Disputes over the lackluster response in tackling the repairs led to five of the seven board members resigning in 2019, The Washington Post reported, citing board meeting minutes and a resignation letter from Wodnicki's predecessor. Some of the members later returned to the board, The Post reported.
Efforts to reach almost everyone who had served on the board since 2018 were unsuccessful, the newspaper said.
Max Friedman, who served on the board from 2011 to 2016, told CNN the board had been plagued by infighting and the resignations made it difficult to get the necessary repairs started.
"I would never quit a board -- I think that's terrible," said Friedman, who lives in Manhattan. When asked about the general sentiment among residents, he said, "there was confusion," and he personally felt the resignations of board members were "inappropriate."
Friedman was careful to note that he didn't think the board could have possibly known that the building was in immediate danger.
"The township didn't tell us," he said.
Following Wodnicki's letter, the condo board association approved the $15 million in repairs, costs slated to be paid by the residents.