One person died and three others are missing after a boat carrying approximately 20 passengers capsized and sank in San Francisco Bay on Tuesday. The incident occurred near Alcatraz Island.

Authorities believe the 50-foot cabin cruiser, named Volare and based out of Stockton, California, was struck by a wave, causing it to overturn. The deceased, an adult male, was taken to shore with severe injuries, and despite CPR efforts, was pronounced dead at the scene. He has not yet been identified.

Three passengers were transported to a local hospital and are reported to be in stable condition, with expectations of release later Tuesday.

San Francisco Fire Chief Dean Crispen stated that passengers were reportedly engaged in a memorial service on the vessel at the time of the incident. The passengers were all adults, with many described as family members.

The U.S. Coast Guard, along with several local authorities, responded to the incident. Rescue swimmers and scuba divers were deployed. The search for the three missing passengers is ongoing and is expected to continue overnight.

The San Francisco Fire Department initially received a call reporting a fire on the boat at 3:30 p.m. local time, though authorities have not yet found evidence of a fire.

Earlier reports indicated 19 people were aboard and two were missing, but these numbers were later revised.