A Honolulu fire investigator has determined a 100-acre wild fire that destroyed at least one unoccupied agricultural building and damaged some crops was intentionally set.

Honolulu fire Capt. Terry Seelig said tips helped police and the investigator determine the cause, but he declined to say how the fire began.

The blaze began about noon by Thompson’s Corner, Seelig said. Firefighters are turning the case over to police, he said.

Six fire companies and four tankers spent today mopping up the fire and received help from a city parks crew to cut down smoldering trees in the area, Seelig said.

A damage estimate has not been released.