The U.S. has opened a criminal investigation into what occurred on a cargo ship before it crashed into Baltimore’s Francis Scott Key Bridge and caused it to collapse March 26, according to a person familiar with the probe. 

Federal Bureau of Investigation (FBI) agents early April 15 boarded the Singapore-flagged container ship, which remains disabled on the Patapsco River, the bureau said in a statement. 

“The FBI is present aboard the cargo ship Dali conducting court authorized law enforcement activity,” the FBI said. “There is no other public information available, and we will have no further comment.”

The Dali lost power and struck the bridge on March 26, killing six workers doing repairs on the span and bringing a halt to cargo traffic at the Port of Baltimore, where shipments of coal, cars and other goods have been disrupted. The container ship and workers on it have remained in place since.

The criminal investigation is examining what kind of failures occurred on the ship, the circumstances leading up to the crash and whether any federal laws may have been broken, according to the person familiar with the matter, who asked not to be identified speaking about information that isn’t public. 

Attorneys representing the Singapore-based ship owner, Grace Ocean Ptd Ltd., earlier this month filed a petition jointly with Synergy Marine Pte Ltd., which was operating the ship. They claim the collapse of the bridge was “not due to any fault, neglect, or want of care” of the companies and that they shouldn’t be held liable for any loss or damage from the disaster. 

But if they are held liable, it shouldn’t be for more than the current value of the ship and its cargo, which has fallen from as much as $90 million to $43,670,000, according to the filing in federal court in Maryland.

The attorneys didn’t immediately respond to a request for comment about the FBI probe.

The investigation was reported earlier by the Washington Post.

Federal investigators looking into what caused the crash are homing in on the vessel’s electrical system, U.S. National Transportation Safety Board Chair Jennifer Homendy said on April 10. The safety board is continuing to investigate and examine data on the ship’s electronic power system and circuit breakers, she said in testimony before a Senate panel.

The U.S. attorney for Maryland, Erek Barron, said his office seeks to hold accountable those responsible for wrongdoing. 

“My office generally will not confirm the existence of or otherwise comment about investigations,” Barron said in a statement. “However, the public should know, whether it’s gun violence, civil rights abuse, financial fraud, or any other threat to public safety or property, we will seek accountability for anyone who may be responsible.”