The National Transportation Safety Board (NTSB) on 6 October launched an investigation on the sinking of the El Faro cargo ship as the US Coast Guard revealed it had discovered more debris in the search area. The Coast Guard released new photographs of the debris found during the ongoing search for survivors on its official Twitter account.

Three photos were posted on the Coast Guard's Southeast account, showing a large piece of metal floating in the ocean as well as unidentifiable debris. In one of the photos, the blue waters appear to be bespeckled with small traces of debris.

The US Coast Guard is continuing its search for the 33 missing crew members and any other perishable evidence, ABC News reported. The NTSB also launched its go-team, which will be charged with collecting perishable evidence as well as looking into logs, maintenance records and the fitness of the captain and crew, to Florida. Investigators also hope to recover the data recorder that was on board the vessel.

NTSB member Bella Dinh-Zarr told reporters the investigation would be difficult because the cargo ship sank in an unknown location, down 15,000-feet, according to Reuters. "It's a big challenge when there's such a large area of water and at such depth," she said. "We hope for the best and that the ship will be recovered."

The cargo ship's owner, Tote Inc said it would "cooperate fully" with the NTSB. "All the information that we have will be made available to them," Tote President and CEO Anthony Chiarello said. "We will find out what happened."

Philip Greene, who heads the ship management subsidiary Tote Services, told reporters that the crew's work in the engine room was unrelated to the propulsion issue reported in the distress call. Greene added that the ship's engine problem made it impossible for the ship to steer away from the severe storm. "I think what's regrettable in this is the fact the vessel did become disabled in the path of the storm, and that is what lead to ultimately the tragedy," he said.

The El Faro lost contact on Thursday (1 October) after reportedly losing power near the Category 4 Hurricane Joaquin. The cargo ship had a crew consisting of 28 Americans and five Polish nationals. On 5 October, the Coast Guard found one unidentifiable body believed to be one of the crew members along with two large debris fields.

The El Faro set sail on 29 September from Jacksonville, Florida on its way to San Juan, Puerto Rico. Thirty-six hours later, the crew issued a distress call saying it had lost propulsion, was listing and had taken on water. It was the last time it was heard from.