https://www.dailymail.co.uk/news/article-9723833/Report-revealed-year-ago-12-story-condo-SINKING-risk.html

REVEALED: Scientists discovered a year ago that 12-story condo was SINKING, it needed extensive repairs for rusted steel and damaged concrete and construction work on roof may have triggered collapse as search continues for 99 missing

Authorities have not yet determined what caused the building to collapse and Miami-Dade police have opened an investigation

Miami-Dade Mayor Daniella Levine Cava said that 'there has been no evidence found of foul play'

The Champlain Towers South sea-view condo development was built in 1981 by the late developer Nathan Reiber's company Nattel Construction

The building sits at at 8777 Collins Avenue in the southeast corner of Surfside but hasn't been updated significantly since then

Florida International University professor Shimon Wdowinski said he knew instantly which building had collapsed when he heard news reports because he had studied the building for a report published last year

According to the study, the building was sinking at a rate of about 2 millimeters a year in the 1990s because it sits on reclaimed wetlands - which could have impacted the building's structure

Surfside Mayor Charles W. Burkett said roof renovations were being done on the property - as some speculated that extra weight could have put pressure onto the building

However, Surfside Vice Mayor Tina said the building passed a roof inspection on Wednesday - the day before the collapse

An engineer who specializes in concrete repair projects told the Miami Herald that one potential structural flaw called 'concrete spalling' jumped out at him when he watched video of the collapse

The engineer, Greg Batista, described the flaw as 'concrete cancer'