Last Updated Mar 16, 2018 9:06 PM EDT
SWEETWATER, Fl. -- Crews have been working non-stop to reach and recover victims of. The death toll is at least six, including 18-year-old Alexa Duran, a student at the school. Her car was crushed by the footbridge. Also, 37-year-old Navaro Brown, a bridge worker who was on the span when it collapsed, died. Two of his co-workers are among the nine injured.
The Florida Department of Transportation said someone from the engineering company left a voicemail for the FDOT that the bridge was "cracking" and "obviously the cracking is not good and something's going to have to be, ya know, done to repair that." The employee was out of the office and did not receive the voicemail until Friday, the FDOT said.
National Transportation Safety Board Chairman Robert Sumwalt said at a press conference late Friday that they are not currently aware of cracks in the bridge and they had not received any tips.
Surveillance video shows the moment 950-tons of concrete and steel collapsed, crushing at least eight cars and shearing others in half. Miami-Dade Police Director Juan Perez announced the search and rescue phase is over. Crews are now.
"We expect to find other individuals down there," Perez said. "So what's probably best is we wait to find all the vehicles and we'll give you a grand total of the fatalities and the magnitude of this event."
On Friday afternoon, crews started the risky job of demolition as investigators began their work, which includes looking into reports a stress-test was being done when the walkway collapsed.
"If this is the case, why was the road underneath open during the stress test," said State Rep. Carlos Curbelo.
In a tweet, Florida Sen. Marco Rubio offered this scenario: "The cables that suspend the Miami bridge had loosened and the engineering firm ordered that they be tightened. They were being tightened when it collapsed."
Plans for the bridge included a tower and cables attached to the walkway, but a week ago, the university and its builders celebrated the installation of the pedestrian span and the "accelerated bridge construction" method - partly developed at the school. It involves building bridge components off-site to minimize traffic interruptions and risk.
The purpose of the $14 million project was to provide a safe path over the busy highway after the death of an FIU student last year.
CBS News spoke to Carol Fraga, who was searching for her husband.
"It's very difficult, the waiting is so ... it's nothing I can imagine," she said.
It's clearly very early on and investigators had to wait for the rubble to stabilize before getting a closer look, but they have acknowledged this is a wide ranging investigation and any suspected wrongdoing could lead to charges.