Another body is recovered from Baltimore's Key Bridge collapse site - as FBI agents begin to probe Dali cargo ship's crew

Another body has been recovered from the site of the collapsed Key Bridge in Baltimore. 

At the request of the family, the victim's name has not yet been revealed.

Video captured the moment the huge structure fell into the river, killing six men - all roadway workers who had been on the bridge at the time. 

This fourth body was found during a search on Sunday when Unified Command salvage teams located what they believed to be one of the missing construction vehicles.

After notifying the Maryland Department of State Police, FBI and Maryland Transportation Authority Police  the victim was found, still trapped inside the vehicle.

Investigators also met with the Baltimore County Mobile Crisis Team and Governor's Office of Immigrant Affairs as they notified family members.

'As we mourn the lives lost and continue the recovery operation, we recognize each missing individual is someone's beloved friend or family member,' said Colonel Roland L. Butler, Jr., Superintendent of the Maryland Department of State Police.

'Along with all of our allied law enforcement partners, we pledge to exhaust the physical and technical aspects of their training while deploying every available resource possible.'

On Monday, the FBI has launched a criminal probe into the collapse that killed the construction workers.

Agents will investigate whether the 22-strong crew of the Dali knew it had serious systemic issues before they left the Maryland port on March 26. 

Some were seen arriving at the ship today to speak to the crew, who remain onboard.  

Meanwhile Baltimore's mayor said the city is bringing in outside firms to 'hold responsible all entities accountable for the Key Bridge tragedy'. 

He has hired two law firms to sue  Grace Ocean Private, the Singapore-based company that owns the ship. 

It comes just three weeks after shocking footage beamed around the world showing the 110,000-ton cargo ship ram into the Francis Scott Key Bridge.

The huge smash caused it to collapse on to the vessel and into the freezing river, sending the six construction workers to their death.

The criminal probe will be overseen by the US district attorney's office in Maryland and focus on how much the 22-crew knew about the ship's problems.

Baltimore mayor Brandon Scott said: 'This unthinkable tragedy has taken Marylanders from their loved ones, and risked the livelihoods of thousands of Baltimoreans who rely on the Port of Baltimore.

'Part of that work needs to be seeking recourse from those who may potentially be responsible, and with the ship's owner filing a petition to limit its liability mere days after the incident, we need to act equally as quickly yo protect the City's interest.' 

There is already a separate federal probe into the deadly collapse of Baltimore's Francis Scott Key Bridge by the National Transportation Safety Board.

During the initial stages of that probe, investigators are focusing on the electrical power system of the massive container ship that veered off course.

Jennifer Homendy, chair of the National Transportation Safety Board, said her agency is gathering data with assistance from Hyundai, the manufacturer of equipment in the ship's engine room. Testifying before a U.S. Senate committee, she said investigators have also requested assistance to examine its circuit breakers.

'That is where our focus is right now in this investigation,' she said. 'Of course, that's preliminary. It could take different roads, different paths as we continue this investigation.'

Homendy said they've zeroed in on the electrical system. The ship experienced power issues moments before the crash, as evidenced in videos showing its lights going out and coming back on.

Investigators are also examining the bridge design and how it could be built with better pier protection 'under today's standards,' Homendy said.

The container ship Dali was leaving Baltimore, laden with cargo and headed for Sri Lanka, when it struck one of the bridge's supporting columns last month, causing the span to collapse into the Patapsco River and sending six members of a roadwork crew plunging to their deaths.

Crews have been working to extract sections of the fallen bridge, including those entangled in a muddy mess at the bottom of the Patapsco River.

'This work is remarkably complex,' Maryland Governor Wes Moore said during a news conference last week. 

Officials said they still expect to open a third temporary shipping channel by late April, which will allow significantly more commercial traffic to pass through the port of Baltimore. The east coast shipping hub has been closed to most maritime traffic since the bridge collapse, which blocked access to its main channel.

Moore said efforts continue to unload shipping containers from the Dali, which will eventually be refloated once pieces of the fallen bridge have also been lifted from its bow. He said crews aim to remove 178 containers; 34 have been removed so far.

Moore also called for bipartisan congressional support to fund construction of a new bridge, saying federal lawmakers came together in 2007 to pay for rebuilding the Interstate 35 bridge in Minnesota after it collapsed into the Mississippi River. He called on members of Congress to visit Maryland and see for themselves.

'Sit down with me and my team, get up close to the wreckage,' he said. 'See what we've been seeing for two weeks. See what it looks like when a steel bridge falls on top of a shipping vessel that is the size of the Eiffel Tower.'

Federal safety investigators remain on scene in Baltimore. They've conducted numerous interviews, including with the ship's pilots and crew members, Homendy said during her testimony Wednesday. She testified at a hearing on her nomination to continue serving as board chair for a second term.

She said the board's preliminary report on the crash will likely be released early next month.

Safety investigators previously laid out a preliminary timeline leading up to the crash, which federal and state officials have said appeared to be an accident.