The FBI has opened a federal criminal probe into the March 26 bridge collapse in Maryland, the Washington Post reported on Monday, citing two US officials familiar with the matter.
The investigation will at least partly focus on the Dali cargo ship and whether its crew left the port in Baltimore knowing the ship had serious problems with its systems, the Post said.
Representatives for the FBI could not be immediately reached to comment on the report.
The head of the US National Transportation Safety Board separately told Congress last week that it had interviewed key cargo ship personnel as part of its investigation of the crash.
Work to clear the wreckage and restore traffic through the Mid-Atlantic state's shipping channel is ongoing after a massive container ship lost power and crashed into a support pylon last month, sending the bridge collapsing into the Patapsco River and killing six bridge workers.