San Diego

The Fire Department arson detail is investigating two early morning fires that occurred within half an hour of each other Friday and resulted in $1.6-million damage to a Mira Mesa office building and $325,000 damage to a Clairemont home, authorities said.

Capt. Ron Cervantes said both the office building, on the 9600 block of Tierra Grande, and the home, on the 3700 block of Cameo Court, are owned by the same person. He said the owner of the properties has been “involved in a family dispute.”

Preliminary investigations indicated that the fire started at two different locations at each property, Cervantes said.

Cervantes said investigators suspect that a chemical was used in the blazes because of their intensity and speed with which they spread.

Charred debris recovered from both sites is being tested to determine whether a chemical was used, Cervantes said.

Fire damage to the office building was confined to the second floor of the two-story structure, Cervantes said. There was extensive water damage on the first floor.

The upper bedrooms in the two-story, single-family home in Clairemont were gutted, Cervantes said. There was extensive water damage to the bottom floor.

It took about 30 firefighters half an hour to control the Mira Mesa blaze, which was reported at 2:24 a.m., a Fire Department spokesman said.

The same number of firefighters were dispatched to the Clairemont fire, which was called in about 2:53 a.m.

Cervantes said no one was injured in either fire.