Four construction workers who were performing overnight maintenance on the Francis Scott Key Bridge at the time of the collapse are still unaccounted for. Two workers were recovered in the water on Wednesday, and the other four are presumed dead.

Authorities said the two whose bodies were recovered on Wednesday were 35-year-old Alejandro Hernandez Fuentes of Baltimore, and 26-year-old Dorlian Ronial Castillo Cabrera of Dundalk, Maryland. They were found in a red truck in an area of water that was 25-feet deep. The search for the other four construction workers has been temporarily put on hold to allow for some of the wreckage to be removed to make the search less dangerous.

Authorities changed the search from a rescue mission to a recovery mission on Tuesday when they said the temperature of water and circumstances of the crash would have made it unlikely for the workers to survive.

In the investigation, federal authorities are working to determine what went wrong in order to cause the crash. In the five minutes leading up to the crash, multiple alarms could be heard and an order to “drop anchor” was recorded on the ship’s data recorder. Shortly before the impact, the ship also suffered a “complete black-out” and issued a mayday warning. The investigation will continue until a cause of the incident has been