BANGOR, Maine — The National Transportation Safety Board on Sunday released underwater images of the wreckage of El Faro, which sank in October with 33 crew members on board during a hurricane off the Bahamas.

The loss of El Faro has been deemed the worst cargo shipping disaster involving a U.S.-flagged vessel since 1983. Five of the crew, including the captain, had connections to Maine.

The 7:30 p.m. release occurred just before “60 Minutes” aired a segment on the NTSB’s investigation on the El Faro disaster. Sunday’s program was the first to show video of the wreckage, located at a depth of 15,000 feet beneath the Atlantic in the infamous Bermuda Triangle.

The program revealed key details about what happened to El Faro in the heavy seas and high winds of Hurricane Joaquin, most notably that the ship’s two-story bridge deck was sheared from the vessel. The ship wreckage and the bridge were found a half-mile apart on the ocean floor.

Also on Sunday night, the NTSB announced that it was opening the accident docket and provided nine underwater images of the wreckage as well as more than 47 minutes of the remotely operated underwater vehicle, or ROV, video of the ship and associated debris field.

At the same time, about two minutes of that video was uploaded onto the NTSB’s YouTube channel.

As the NTSB conducted its investigation into El Faro’s sinking, it allowed “60 Minutes” to report on its activities. Scott Pelley reported from aboard the U.S. Navy’s salvage and diving vessel Apache for the story.

Tom Roth-Roffy, the NTSB’s lead investigator on the El Faro case, is looking at many factors to determine the cause of the sinking.

“This is the most difficult and complex investigation I have ever worked on in my 17 years with the National Transportation Safety Board,” he said. Despite many hurdles, including the great depth at which the wreck lies, Roth-Roffy is confident he will be able to determine a cause.

“We’ve experienced this sort of challenge before on other investigations and we’re hopeful that we will be able to determine the cause of the sinking,” Roth-Roffy told Pelley.

A major challenge for Roth-Roffy is the absence of the ship’s Voyage Data Recorder, or VDR, which would give him and others access to the conversations on El Faro’s bridge that could offer more clues. The device went missing when the vessel’s top two decks — including the bridge, where the captain would have been — were shorn off.

The ROV did not find any remains of the crew members.

The footage that aired on “60 Minutes” was taken by cameras attached to the Apache’s cable controlled underwater recovery vehicle. The images they recorded disturbed Roth-Roffy.

“We were looking, of course, for the bridge and the Voyage Data Recorder … we got up to that level and to see just openness, is extremely moving and difficult … it was a very big surprise,” says Roth-Roffy of the realization that some of the crew may have been swept away with the two decks.

Pelley also spoke with family members of some of those lost at sea and to the chairman of the NTSB, Christopher Hart, who said it may take up to a year to answer all the questions surrounding the sinking of the El Faro.

Among the family members interviewed for the story was Deb Roberts of Jay, whose son Michael Holland was part of El Faro’s crew. The 25-year-old was a 3rd assistant engineer on the cargo ship when it sank during Hurricane Joaquin.

“I’m not a professional. I’m not an engineer. I’m a business manager,” she said when Pelley asked where she thought the responsibility for the disaster lies. “I think it was a series of unfortunate events, and without any other information I truly blame it on Hurricane Joaquin.”

The NTSB contracted with the U.S. Navy to find the 790-foot El Faro, which disappeared on Oct. 1 during Hurricane Joaquin while on a regular weekly cargo route between Florida and Puerto Rico after the captain reported losing propulsion and taking on water. The crew included 28 Americans and five Poles.

The last communication between the steamship and the mainland was made at 7:20 a.m., according to previously published reports. The cargo carrier lost propulsion and was listing after encountering Hurricane Joaquin north of San Salvador Island in the Bahamas, the captain said in his request for help.

Among 33 crew members lost aboard the ship were 53-year-old Capt. Michael Davidson of Windham, a 1988 graduate of Maine Maritime Academy; Michael Holland, 25, of Wilton, a 2012 graduate of Maine Maritime; Danielle Randolph, 34, of Rockland and a 2004 graduate of Maine Maritime; and Dylan Meklin, 23, a 2010 graduate of Rockland District High School and a 2015 graduate of Maine Maritime. Another crew member, Mitchell Kuflik of Brooklyn, New York, graduated from Maine Maritime in 2011.

A search team aboard the the Apache found the wreckage of El Faro on Oct. 31. The vessel was found at a depth of about 15,000 feet near its last known position, just off Crooked Island in the southern Bahamas.