SANTA BARBARA, Calif. – All 33 passengers and one crew member are assumed dead after a tragic boat fire early Monday that occurred in open water off the California coast.

Authorities reported in a press conference Tuesday that the remains of 20 victims had been recovered, including 11 females and 9 males. Fourteen victims remain missing. Approximately four to six bodies were discovered in the wreckage but were unable to be recovered by nightfall.

U.S. Coast Guard Capt. Monica Rochester announced that the Coast Guard was suspending search efforts, as “no additional signs of distress or debris has been witnessed.” Rochester said the nearly 24-hour search operation included seven missions and three helicopters crews, covering an area of 160 miles.

The boat had six crew members and the 33 passengers when it became fully engulfed in flames during a recreational scuba diving trip. The passengers and one crew member were assigned to bunk-beds on the bottom of the deck. Five crew members sleeping on the top deck jumped off and took a dinghy to safety. Two had minor injuries.

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The crew members took their dinghy to a private fishing boat, The Grape Escape, that was anchored near the north shore of Santa Cruz Island. The boat’s owners said two of the crew members went back to look for survivors but found no one. 

Investigators have yet to determine the cause of the fire. Authorities said Tuesday that there was no indication that an explosion had occurred. Passengers were unable to get out because both the main stairwell and escape hatch were likely blocked by fire. It is unclear if passengers were actually asleep when they perished, Rochester said.

Rochester said the boat was equipped with a fixed firefighting system, as well as various portable extinguishers. She could not immediately confirm when the system was last tested.

Santa Barbara County Sheriff Bill Brown said the victims range from teenagers to senior citizens. A majority appear to be from the Santa Cruz region.

Authorities had not confirmed the victims’ cause of death, and autopsies were underway. Brown said that many, if not all, of the victims will need to be identified through DNA analysis. Investigators will be coordinating with family members to collect DNA samples for comparison purposes.

“The devastating impact on so many families and so many people in this community is evident. That is certainly very troubling,” Brown said.

Brown said the boat was upside down in relatively shallow water with receding tides that were moving the vessel around. A 3,000-foot temporary flight restriction was established around it. Authorities said it was under discussion whether to tow the vessel to shore or examine it on site.

Authorities opened a family assistance center where counseling was being provided to relatives of those onboard. None of their names were immediately released.

At least two students and their parents, whom may have been aboard during the incident, were reportedly from Pacific Collegiate School in Santa Cruz, according to KCBSTV. 

“Our hearts and prayers are with the families of the victims and those yet missing, particularly those of our students,” Head of School Maria C. Reitano said in a statement sent to the Salinas Californian. “Right now, our priority as a school community is to support our students, staff, and families.”

Authorities responded Monday to a 3:30 a.m. mayday call of a boat engulfed in flames off Santa Cruz Island, about 90 miles northwest of Los Angeles, the Coast Guard said at a news conference later that day.

“The call was garbled, it was not that clear, but we were able to get some information out of it to send vessels,” said Coast Guard Petty Officer Mark Barney.

Coast Guard crews, the Ventura County and Santa Barbara County fire departments, and Vessel Assist responded to the call regarding the 75-foot commercial diving vessel called Conception and operated by Truth Aquatics out of Santa Barbara Harbor.

The boat had been anchored in an area called Platts Harbor at Santa Cruz Island, part of the five-island Channel Islands National Park and technically a part of Santa Barbara County.

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Truth Aquatics, a Santa Barbara-based company, was founded in 1974. It had been chartered by Worldwide Diving Adventures, which says on its website that it has been taking divers on such expeditions since the 1970s.

The names of the passengers on the boat were not available as of Monday evening. Truth Aquatics said the list of all the people aboard was in the hands of the Coast Guard.

Authorities said Monday afternoon they were still working to notify next of kin of those who died. Four families had not yet been connected with investigators as of Tuesday.

A spontaneous memorial for the victims popped up at Santa Barbara Harbor Tuesday. Jennifer Stafford came to the seaside memorial with heart-shaped pins and flowers to tie to the wharf. The longtime Santa Barbara woman said she wanted to find a way to help.

“I just brought them along to see if I could give them to family members so they would have a touchstone,” she said, after hugging a woman who said she had a family member who was still missing. The woman wore one of Stafford’s pins.

Stafford said one man had a fallen to his knees sobbing at the memorial, where flowers, leis and candles had been left. A pair of flippers hung from a post with the words “We love you Conception” written on them.

“People are in shock,” Stafford said. “If they lost a family member or best friend or coworker … it’s shocking and it’s so sad.”

Rodriguez reported out of McLean, Virginia. Hauck reported out of Chicago. Contributing: Cheri Carlson, Gretchen Wenner and Megan Diskin, Ventura County (California) Star; The Associated Press.