Some disturbing new details have emerged as authorities examine the cause of a bridge that collapsed over an eight-lane highway less than a week after it was put in place, killing six people near Miami, Florida.

NBC News and other media outlets are reporting that cracks were found on the bridge days before the collapse of the 950-ton bridge was an overpass for students to walk from Florida International University to nearby Sweetwater, Florida. And then comes word that engineers may have been tightening cables to that bridge the morning of its deadly collapse.

The Florida Department of Transportation (FDOT) released a voicemail Friday (March 16, 2018) that told officials of the cracks that were spotted and in need of repair, but the person did not get Tuesday's message until Friday because the employee was out of the office, according to media reports. The bridge collapsed Thursday about 1:30 p.m., crushing vehicles below and killing at least six people and injuring at least 10 others. 

Investigators from the National Transportation Safety Board (NTSB) are on site examining the probable cause of the collapse and have not confirmed the news about the cracks in the bridge. Some elected officials in Florida also stated at a press conference that following stress tests on the bridge Thursday morning, workers were tightening loose cables, but no exact cause of the collapse has been determined yet.

FDOT told the media that engineers for the project had a permit that allowed them to close Tamiami Trail below the bridge but the design team reportedly never made that request. It also has been reported that the bridge was not open for pedestrian traffic yet because construction was still left to build a tower that would have supported the walkway from above with cables. That tower reportedly had not yet been constructed but it is unclear what was supporting that part of the bridge before its collapse.

The $14.2 million bridge was prefabricated with some of its elements made in a factory and then shipped to the site in a method used since 2010 called accelerated bridge construction (ABC).

Stories also are coming out of the heroes at the scene - passersby who were at the scene desperately trying to save who they could beneath the rubble before rescue workers arrived. Workers are still removing vehicles from under the 950 tons of rubble as what is now termed recovery efforts continue across the 175-foot span on the highway.