Baltimore (AP) — Attorneys are asking a federal judge to prevent crew members on the cargo ship Dali from returning to their home countries amid ongoing investigations into the circumstances leading up to the deadly collapse of the Francis Scott Key Bridge in March.

Eight of the Dali’s crew members were scheduled to debark the ship and return home as early as Thursday, according to emails included in court filings Tuesday. The roughly two dozen total seafarers hail from India and Sri Lanka.

That would mark the first time any of them can leave the ship since it lost power and crashed into one of the bridge’s supporting columns shortly after leaving Baltimore on March 26.

In the court filings, attorneys representing the City of Baltimore said the men should remain in the U.S. so they can be deposed in ongoing civil litigation over who should be held responsible for covering costs and damages resulting from the bridge collapse, which killed six construction workers and temporarily halted most maritime traffic through Baltimore’s busy port.

“The crew consists entirely of foreign nationals who, of course, have critical knowledge and information about the events giving rise to this litigation,” attorneys wrote. “If they are permitted to leave the United States, Claimants may never have the opportunity to question or depose them.”

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The petition requested an emergency hearing on the matter. No ruling has been issued in response.

Darrell Wilson, a spokesperson for the ship’s owner, said Tuesday evening that some crew members are scheduled to leave.

“A portion of the crew are going home and a portion are remaining here to assist with the investigation,” he said in a text message.

Wilson said he was unable to provide additional details about how many crew members were leaving and when. He also said he wasn’t sure when the ship itself would leave Baltimore for Norfolk, Virginia, where it will receive more extensive repairs.

The hulking container ship remained pinned amid the wreckage of the fallen bridge for almost two months while workers removed thousands and thousands of tons of mangled steel and concrete from the bottom of the Patapsco River at the entrance to Baltimore’s harbor.

The ship’s crew remained onboard even when explosives were detonated to break apart fallen bridge trusses and free the vessel from a massive steel span that landed across its bow.

The ongoing civil litigation began with a petition from the ship’s owner and manager, two Singapore-based companies, seeking to limit their legal liability for the deadly disaster.

A National Transportation Safety Board investigation found the ship experienced two power outages in the hours before it left the Port of Baltimore. In the moments before the bridge collapse, it lost power again and veered off course. The agency’s investigation is still ongoing to determine what exactly caused the electrical issues.

The FBI also launched a criminal investigation.

According to the emails included in Tuesday’s court filings, the eight crew members scheduled to return home have already been interviewed by Department of Justice investigators and that the department doesn’t object to their departure. The crew members will fly out of Baltimore “likely on or about June 20th,” an attorney for the ship’s owner and manager wrote.