Divers recovered the bodies of 20 of 34 people believed to have been killed after a fast-moving fire broke out aboard a dive boat off California‘s Santa Cruz Island, trapping the victims below deck.
Search and rescue efforts were called off and recovery moves were underway, the Santa Barbara County Sheriff and U.S. Coast Guard officials told a press conference on Tuesday.
Authorities will use so-called rapid DNA technology to identify the bodies, 11 females and 9 males, authorities said.
Other bodies were seen in the underwater wreckage. When water and weather conditions stabilize, crews will attempt to recover the remaining 14.
Flames ripped through the scuba diving vessel Conception, as it was moored off Santa Cruz Island early Monday morning. Five of the six-strong crew managed to escape in an inflatable boat.
The boat sank later in the morning and was currently lying upside down under more than 60 feet (18 meters) of water, police said.
Witnesses reported hearing a number of explosions, but authorities said it was too early to say what caused the fire. Santa Barbara County Sheriff Bill Brown said scuba or propane tanks on the Conception may have blown up in the flames, but there was no indication an explosion preceded the blaze.
The federal National Transportation Safety Board said it had sent a team of engineers and fire specialists to investigate the blaze.
WATCH: Sheriff says fatal boat fire was ‘worst case scenario’
There were a total of 33 passengers and six crew members onboard the Conception, a 75-foot boat, when the fire started at about 3:15 a.m. (1015 GMT) on Monday, officials said.
The surviving crew members sought refuge on a fishing boat moored nearby, banging on the side to wake up Bob Hansen and his wife, who were sleeping onboard.
“When we looked out, the other boat was totally engulfed in flames, from stem to stern,” Hansen told the New York Times. “There were these explosions every few beats. You can’t prepare yourself for that. It was horrendous.”
After borrowing clothes from the Hansens, some crew members headed back toward the Conception to look for survivors without luck, Hansen said.
Investigators said a single mayday call came from the boat reporting the fire.
WATCH: U.S. Coast Guard details rescue efforts in response to ‘tragic’ diving boat fire
“It happened quickly enough so many people could not get off,” U.S. Coast Guard Lieutenant Commander Matthew Kroll told CNN.
The diving boat was chartered by Worldwide Diving Adventures, a Santa Barbara, California, excursion firm. It said on its website that the Conception was on a three-day excursion to the Channel Islands, and was due back in Santa Barbara at 5 p.m. on Monday.
The boat‘s owner, Truth Aquatics, referred queries about the accident to a joint media center. “This is still an ongoing search and rescue,” it said.