(CNN)[Breaking news update, published at 9:05 p.m. ET]
Construction crews were working on diagonal components on the north end of a future pedestrian bridge when the structure collapsed, National Transportation Safety Board investigator in charge Robert Accetta said Friday night. Accetta said the crews were applying post-tensioning force to strengthen diagonal members.
Also Friday night, the Florida Department of Transportation said the lead bridge engineer with the firm that designed the bridge left a voicemail for the DOT on Tuesday, warning of cracking along the bridge span.
The DOT did not find the voicemail until Friday, the department said in a news release.
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