Investigators on Monday were looking into the cause of a fire that gutted a garage at the Diamond Head home of "Hawaii Five-0" star Alex O’Loughlin.

Honolulu Fire Capt. Terry Seelig said damage to the Maka­lei Place garage and its contents was $110,000.

"Flames were rolling out of the garage when firefighters arrived," Seelig said. "It was fully developed."

Next-door neighbor Muriel Lighter said she was near her pool when she heard a loud boom.

"It was like a blast, like someone was kicking in the garage door," Lighter said.

She said she saw smoke and then flames and then yelled for anyone to get out. No one came at first, but then she assisted a woman who climbed over the fence, she said.

Seelig said no one was hurt in the fire, which started at 3:47 p.m. Forty firefighters from five engine companies and two ladder companies responded to the two-alarm fire, which was under control at 4:11 p.m.

An apartment above the garage was not damaged, he said.