RICHMOND -- A couple died and their son was critically injured in a house fire that destroyed a garage converted into a residence early Friday, Richmond fire officials said.

The couple, 56-year-old Mearen Lee Pon and 50-year-old Bounkeo Viengvilai,¿ perished from smoke inhalation in the blaze on the 600 block of 21st Street, fire officials said. Their 28-year-old son was taken to Saint Francis Memorial Hospital in San Francisco with burn injuries. He is expected to recover.

Fire crews were called to the blaze at 2:37 a.m. and found the converted garage engulfed by flames, Battalion Chief Manly Moulton said. The one-alarm fire was under control 10 minutes after firefighters arrived and crews found the couple deceased inside the structure, he said.

Richmond Fire Marshall Terry Harris answers questions about the fatal fire in Richmond, Calif. on Friday July 5, 2013. (Robert Rogers/Bay Area News Group)
Richmond Fire Marshall Terry Harris answers questions about the fatal fire in Richmond, Calif. on Friday July 5, 2013. (Robert Rogers/Bay Area News Group)

The injured man was found outside and on fire. "They extinguished him immediately," Fire Marshal Terry Harris said. The victims were part of a family of eight living on the property, with the parents and son in the converted garage and other family members living in the main residence.

Friday morning, firefighter tools such as shovels and a pickax could be seen, half-submerged in ashes. Beer bottles and charred clothing were strewn across the blackened grasses near the front entrance of the small house.

Harris said investigators would know sometime next week what caused the deadly blaze.

Relatives and neighbors said the family had immigrated from Laos in the 1990s. Richmond has had a large and tight-knit Laotian community since the 1970s.

"My wife and I called 9-1-1," said Robert Jenkins, who lives a few houses away. "The wind was blowing the embers all over our house, and I ran out and with another guy started spraying the flames with a garden hose, but it was too much."

Harris said fire officials have ruled out an electrical cause of the fire and that melted barbecue pits visible Friday were not the cause. Harris said cigarette butts were found throughout the house, and fireworks were present as well.

"We haven't ruled smoking or fireworks out," Harris said.

Fire officials and neighbors said the narrow street was the scene of a lively party Thursday night, with many people exploding fireworks. But the activity had long ended before the 9-1-1 calls.

"It's just a shame," Jenkins said. "It was a nice night in the neighborhood, but the way it ended is tragic."

Contact Rick Hurd at 925-945-4789 and follow him at Twitter.com/3rdERH. Contact Robert Rogers at 510-262-2726 and follow him at Twitter.com/roberthrogers.