(SANTA BARBARA, Calif.) -- In a preliminary report on the Southern California blaze that erupted on an anchored dive boat and killed 34 people, federal investigators revealed that surviving crew members told them there were no known mechanical or electrical issues with the vessel and smoke detectors sounded in the below-deck bunkroom where the victims were sleeping.
The National Transportation Safety Board released the preliminary report on Thursday, a day after divers recovered the body of the final missing victim of a boat fire off the coast of Santa Barbara.
Salvage teams were working Thursday to raise the doomed ship from 65 feet of water so investigators could closely inspect the vessel as part of their probe to determine what sparked the Labor Day fire and if any criminal charges are warranted.
NTSB officials said the investigation could take 12 to 24 months, but they are "100% certain" they will determine the cause of the fire.
The Santa Barbara County Sheriff's Office announced on Twitter Wednesday that it "is relieved to report that search and recovery efforts today were successful in locating the last missing victim."
DNA testing is still being conducted to confirm the identities of seven of the 34 victims recovered, the sheriff's office said.
The bodies were pulled from the submerged wreckage of a chartered dive boat that caught fire before dawn on Sept. 2 near the Channel Islands, about a mile off the coast of Santa Barbara.
There were 39 people aboard the 75-foot vessel, named the Conception, when it burst into flames. Five crew members, including the captain, who were all on the top deck jumped overboard and survived. The 34 others were apparently sleeping below deck and became trapped when flames blocked both a stairway and an escape hatch, according to the sheriff's office.
The burning boat sank in 65 feet of water and overturned as firefighters battled the flames. A day later, the U.S. Coast Guard called off the search for possible survivors, shifting its efforts to search and recovery.
DNA collected from family members is being used to identify the victims, who are believed to range in age from in their teens to their 60s, according to the sheriff's office.
The NTSB sent a 16-member investigative team to the scene last week. They are collecting evidence and expected to interview the crew, witnesses and first responders, according to NTSB member Jennifer Homendy.
During an interview with ABC News last week, Homendy said the crew members tried to get to the passengers sleeping below deck but were pushed back by fierce flames. They then went to the front of the ship and tried to break through its windows. When that didn't work, they ultimately had to look out for their own safety.
"At some point because of heat, smoke and fire they had to jump off the boat," she said.
The boat was required to have smoke detectors, fixed firefighting equipment in the engine room and fire extinguishers throughout, including ones at the front and rear of the vessel, according to Capt. Monica Rochester of the U.S. Coast Guard, who told reporters last week that all the required firefighting apparatus was accounted for during the most recent inspection.
It remains under investigation whether the crew attempted to use the firefighting equipment before abandoning ship, Rochester said.
Copyright © 2019, ABC Radio. All rights reserved.