The U.S. investigation into the deadly sinking of the El Faro cargo ship during a hurricane last fall shifted direction on Friday, as the Coast Guard wrapped up its initial public hearings on the accident that killed all 33 people onboard.

The agency will now wait to see if key evidence can be recovered from the shipwreck. In April, searchers will make a second attempt at finding a voyage data recorder that could provide detail on the ship's sinking off the Bahamas.

The recorder, similar to an airplane's black box, may hold data on the last 12 hours of a voyage that saw the worst cargo shipping disaster involving a U.S.-flagged vessel in more than three decades.

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The Coast Guard's Marine Board of Investigation, convened only for the most serious accidents, for the past two weeks has heard testimony on events leading up to the disaster on Oct. 1.

The panel listened to the doomed captain’s recorded final call for help as his vessel took on water, and his warning that the "clock was ticking."

Executives of Tote Services, which operated the El Faro, testified that they had paid little or no attention to the worsening storm or to communications from the captain on a weekly route between Florida and Puerto Rico.

Captain Michael Davidson, a veteran mariner from Maine, was solely responsible for all decisions that ended in disaster, Tote executives testified. Company leaders previously have blamed the accident on an unexplained loss of power.

Jason Itkin, a Houston lawyer who is suing Tote on behalf of four crew members’ families and has followed the hearings, said on Friday that their statements seemed tailored to limit the company's liability.

The Coast Guard plans a second round of hearings to focus on greater detail on the fatal trip. While no date is scheduled, the panel is expected to reconvene by early summer.

But if the recorder is found, the second phase could be delayed while investigators thoroughly analyze its contents, Coast Guard spokeswoman Alana Ingram said.

A salvage team failed to locate the recorder, which dislodged from the ship’s bridge, during a search last November.

Ultimately, the Coast Guard panel expects to issue a report and could make recommendations on issues from ship standards to action on licenses of those involved in the disaster.

Any criminal activity uncovered would be reported immediately to the U.S. Justice Department, Ingram said.