The cause of fires that destroyed a Makaha house for recovering substance abusers and a home in Wahiawa could not be determined.

Fire investigators have completed their investigations into the fires on Olive Avenue in Wahiawa on Saturday and in the 84-800 block of Lahaina Street in Makaha on May 3, Honolulu Fire Department Capt. David Jenkins said Tuesday.

In both cases, the damage was too extensive to determine the exact location of the fire’s origin and the manner in which the fire started, Jenkins said.

Both cases have been closed, but can be reopened if new information comes up.

The fire on Saturday started on the 200 block of Olive Avenue at about 3:50 p.m. and destroyed a one-story single-family home, causing $200,000 in damage to the structure, contents and neighboring property. Five people were displaced.

Twenty-two people lived at the Lahaina Street house, which caught fire at about 5 a.m. May 3. One man sustained burns to his arm in the fire.

The blaze destroyed the single-story structure and caused more than $600,000 in damage to the structure, contents and several neighboring structures and vehicles. Six people from a neighboring home were also displaced.

Firefighters described the property as a “clean and sober” house, and a relative of a man who was living at the property said he lived there with others who had undergone substance abuse rehabilitation.

The city Land Use Ordinance requires a conditional-use permit if more than eight unrelated people live in a residence. The city said it does not have such a permit on file for the property.