Probe will examine circumstances leading up to cargo ship’s collision with the Francis Scott Key Bridge, sources say.

The Dali collided with the Francis Scott Key Bridge on March 26. The FBI said on Monday that it had boarded the ship to conduct “court-authorised” law enforcement activity regarding the crash, an agency spokesperson told the Reuters news agency.

There is no other public information available, and the FBI will have no further comment, the spokesperson said.

The cargo ship crashed into the bridge about 1:30am (05:30 GMT) on March 26 and caught fire. In a spectacular moment of destruction caught on video, the bridge buckled and collapsed into the water and onto the ship.

Six people who were working on the bridge at the time of the collision were killed. Divers have recovered three of the six bodies.

Citing an unnamed source familiar with the FBI investigation, The Associated Press news agency reported the inquiry would centre on the events leading up to the crash and whether all federal laws were followed.

The Washington Post also reported that the investigation would “look at least in part at whether the crew left the port knowing the vessel had serious systems problems”, according to two US officials familiar with the matter.

News of the FBI investigation came as Baltimore Mayor Brandon Scott announced that the city was partnering with two law firms “to launch legal action to hold the wrongdoers responsible” and mitigate harm from the bridge’s collapse.

Scott said the city “will take decisive action to hold responsible all entities accountable for the Key Bridge tragedy, including the owner, charterer, manager/operator, and the manufacturer of the M/V Dali, as well as any other potentially liable third parties”.

“We are continuing to do everything in our power to support everyone impacted here and will continue to recognize the human impact this event has had,” the mayor said in a statement on Monday morning.

The Dali is managed by Synergy Marine Group and owned by Grace Ocean Private Ltd, both of Singapore. Danish shipping giant Maersk chartered the Dali to sail to Sri Lanka.

“Due to the magnitude of the incident, there are various government agencies conducting investigations, in which we are fully participating,” Synergy Marine spokesperson Darrell Wilson said in a statement Monday.

“Out of respect for these investigations and any future legal proceedings, it would be inappropriate to comment further at this time.”

Safety investigators have recovered the ship’s “black box” recorder, which provides data on its position, speed, heading, radar, bridge audio and radio communications as well as alarms.

Last week, the head of the US National Transportation Safety Board separately told Congress that its investigators had interviewed key cargo ship personnel as part of its investigation.

Work to clear the wreckage and restore traffic through the port’s shipping channel continues.