The Conception was on the final night of its three-day Labor Day weekend voyage to the Channel Islands when it caught fire, according to the National Transportation Safety Board.
Investigators continued Friday to probe the source of the blaze. Unidentified law enforcement sources told The Los Angeles Times last week that a preliminary investigation "suggested serious safety deficiencies aboard the Conception," including the lack of a roaming night watchman and inadequate training for crew members in the event of an emergency.
Jennifer Homendy, an NTSB board member, previously said investigators were examining the engineering and wiring of the 75-foot Conception, according to CNN.
"We are aware that there was a lot of gear on board with the cameras and the crew, cameras, phones, extra batteries. And chargers," she said.
Officials with NTSB said a crew member woke early on Labor Day to find flames licking up from the salon in the forward, starboard corner of the compartment. Crew members radioed a distress message to the Coast Guard and tried to access the compartment where the other crew member and the passengers were sleeping, but officials said the compartment was fully engulfed by the fire. One surviving crew member suffered a broken leg as the crew tried to reach the others onboard.
Eventually, they jumped overboard.
Two crew members and the boat's captain re-boarded the vessel, according to the NTSB, but they were still unable to get to the other people on board the ship. They launched a skiff to rescue the two crew members who remained in the water and sought help from a boat anchored nearby, a recreation vessel dubbed the Grape Escape.
Authorities said Wednesday that they recovered the last of the victims of the water. Officials were using DNA testing to confirm their identities.