Search crews have recovered the bodies of 33 people who died when a chartered dive-boat caught fire and sank off the coast of Santa Barbara, California, officials said Wednesday.
One passenger believed to have perished in the Labor Day disaster remains missing, the Santa Barbara County Sheriff's Department said.
The sheriff's department said in a statement that 13 bodies were recovered by nightfall on Tuesday, a day after 20 were pulled from the Pacific Ocean floor.
"They have not yet been identified by the coroner, but our search shows that we have one remains outstanding," the statement reads.
(MORE: Brother of boat fire victim speaks out: 'Cherish every moment, breath by breath')As the search-and-recovery mission continued near the Channel Islands, about a mile off the coast of Santa Barbara, the National Transportation Safety Board launched an investigation into what caused the calamity.
"I am 100% confident that our investigators will determine the cause of this fire, why it occurred, how it occurred and what is needed to prevent it from happening again, absolutely," Jennifer Homendy, a member of the NTSB, said at a news conference Tuesday evening.
The recovery of the additional bodies came a day after the U.S. Coast Guard announced that the search-and-rescue mission has been suspended and has now become a search-and-recovery effort.
There were 39 people aboard the 75-foot ship named the Conception when a fire erupted about 3:30 a.m. local time on Monday, officials said. Five crew members, including the captain, jumped overboard and were rescued by a nearby good Samaritan vessel, officials said.
The 34 people killed in the disaster were apparently asleep in the lower deck of the three-deck boat, officials said. The flames apparently blocked a stairway leading to the upper decks and an escape hatch, trapping the victims, Santa Barbara County Sheriff Bill Brown said on Tuesday.
The ship sank and overturned in about 65 feet of water as firefighters battled the flames, Brown said.
Homendy said a 16-member investigative team from the NTSB arrived on scene Tuesday morning. They're collecting evidence and expected to interview the crew, witnesses and first responders.
NTSB investigations of such "major marine casualty" incidents typically take 12 to 24 months to complete, but the agency usually releases a preliminary report within 10 days of an incident, she added.
Brown said the victims ranged in age from 17 to in their 60s. He said DNA collected from family members is being used to identify the victims.
The boat had been chartered by Truth Aquatics in Santa Barbara and was on the last day of a three-day diving adventure trip off the Channel Islands, Brown said.
Dominic Selga told ABC News that his mother, stepfather and three sisters were among those who died.
"Just thinking about that is difficult," Selga said. "Being burned alive, burning while drowning, while inhaling smoke, that's insane."
Capt. Monica Rochester of the U.S. Coast Guard said the boat was required to have smoke detectors, fixed firefighting equipment in the engine room and fire extinguishers throughout the vessel, including ones at the front and rear of the boat. She said that during the most recent inspection of the boat, all the required firefighting apparatus was accounted for.
Rochester said it remains under investigation whether the smoke detectors were working at the time of the fire and if the crew attempted to use the firefighting equipment before abandoning ship.
Colleagues of the boat's skipper, Boylan, who has not yet spoken of the disaster, defended him as an extremely safety-conscious mariner.
"There's no better captain than Jerry. No one," Dana Fritzler, the wife of the owner of the Conception, Glen Fritzler, said in a statement to ABC affiliate station KEYT-TV in Santa Barbara. "He kept everything on his boat immaculate and safe."
Ian Higgins, captain of the Conception's identical sister ship called the Vision, told ABC affiliate station KGTV in San Diego, that Boylan is a stickler for safety.
"He's so safety conscious about all the different aspects of the vessel," Higgins said of Boylan. "He's about as stern as a mariner, as stern as a captain, as stern as an individual and safety conscious as an individual as one can be."