A fire department inspector is investigating the cause of a blaze that destroyed a two-story structure early Sunday near Manini Beach in the vicinity of Kealakekua Bay.

Firefighters arriving at the scene at 82-6023 Kahauloa Rd. at 3:34 a.m. found the structure had collapsed in flames.

A fire department spokesman said the building burning was a secondary structure not connected to the main house and contained a garage, kitchen and living area, with an office and storage area on the second floor.

Neighbors were using garden hoses to keep the fire from spreading.

It took firefighters nearly four hours to extinguish the flames.

Damage was estimated at $110,000.