Emergency crews responded after receiving reports at about 3:35 p.m. local time of a boat on fire approximately 600 yards (550 meters) off Alcatraz Island, according to San Francisco Fire Chief Dean Crispen. By the time rescuers reached the scene, the vessel had overturned.

Rescue personnel immediately began lifesaving efforts on one victim recovered from the water. The individual was transported to shore while receiving cardiopulmonary resuscitation but was later pronounced dead.

“We still have two missing and one deceased dog,” Crispen said in remarks shared by San Francisco Mayor Daniel Lurie’s office.

The search for the two missing passengers continued into the night, with helicopters, fixed-wing aircraft and rescue boats from the San Francisco Fire Department, local police and the U.S. Coast Guard combing the waters around the island.

San Francisco Fire Department Lt. Elias Mariano said search operations would continue overnight as authorities worked to locate the missing individuals.

Officials said the vessel was a privately owned cabin cruiser motorboat registered in Stockton, California. Authorities have not determined whether it was traveling to Alcatraz, one of San Francisco’s best-known tourist destinations and the site of the former federal prison that now attracts visitors from around the world.

The cause of the incident has not been disclosed, and investigators have not indicated whether the reported fire contributed to the boat’s capsizing.

Authorities confirmed that 16 of the 19 people aboard were rescued. At least one survivor sustained serious injuries after entering the water, according to the Los Angeles Times.

Television footage broadcast by local stations showed the vessel’s final moments before it disappeared beneath the waters of San Francisco Bay.

Emergency officials have not released the identities of the deceased or the missing, and no additional information about the passengers was immediately available.

The incident triggered a coordinated response from multiple agencies as rescue teams continued searching the bay for survivors while investigators worked to establish the circumstances that led to the sinking.