Nine people are still missing after a deadly boat fire off Santa Cruz Island in California.

Officials say at least 25 people are dead after the 75-foot boat caught fire early Monday morning.

More than 30 people were trapped in the sleeping quarters below deck of the charter boat as it went up in flames off Santa Cruz island.

Five crew members, who were awake above deck, jumped off and were picked up by a nearby boat. Parts of the burned ship sunk.

Santa Barbara County sheriff, Bill Brown, says they couldn't ask for a worse situation.

"39 souls were reported to be on that vessel when it left Santa Barbara. Five victims were subsequently rescued" said Brown. 

Authorities say the passengers on board were experienced scuba divers, and the charter boat's operating company has an excellent safety record.

Tuesday morning, investigators are still working to determine what caused the boat to catch fire.