A fire at two abandoned Waikoloa buildings formerly used as a preschool did an undetermined amount of damage early yesterday.

Firefighters called to the scene on Quarry Road at 12:29 a.m. found the two structures fully involved in flames, with the fire spreading to the surrounding brush.

Eight fire units brought the blaze under control at 1 a.m.

The fire destroyed the two buildings belonging to Waikoloa Mauka LLC and burned about a half-acre of brush, fire officials said.

The cause of the fire is under investigation, and police were interviewing witnesses to determine if it might have been caused by a bonfire that burned out of control.