What gave it away, the ship losing power twice in the span of a minute or so, only getting restored, but it was too late when it was headed directly to the bridge.
NTSB Chair Jennifer Homendy briefs the media on the NTSB investigation of a cargo ship striking and subsequent collapse of the Francis Scott Key Bridge in Baltimore, Maryland.
https://www.youtube.com/watch?v=FczgLhdqw0M