Scott G. Winterton, Deseret Morning News
Salt Lake fire investigators Wyman Berg, left, and Crystal Dongen begin their search for the cause of a fire Monday in Salt Lake City.

Salt Lake City fire investigators say a house explosion early Monday morning was the result of arson.

It's the second time in 18 months crews have responded to an arson-caused fire at that house. But investigators were unsure Monday morning if the same family lived in the house for each incident.

No one was injured in Monday's blast, although for a while investigators did not know what had happened to the home owner. The two adults and a child who lived at the house were found safe about 2 p.m., said Salt Lake Fire Capt. Karleen Montanez. Investigators were scheduled to interview the adults Monday afternoon.

Officials say the family was not home at the time of the explosion, but it was unclear Monday where they were. Montanez also did not know where the family was found Monday afternoon.

Just before 3 a.m., a house near 300 North and 1040 West blew up.

"The north wall completely exploded off. The windows exploded out clear to the other side of the street. Glass was in the gutter on the other side of the street," Montanez said.

The fire also singed the siding off an adjacent home.

The nearest fire station was just a block away. The explosion woke the firefighters who got up to see what was happening. When they reached the house it was fully engulfed, Montanez said.

Initially, crews believed the house was vacant, she said. They discovered later, however, that a family had recently moved in. A family member showed up at the house later and told investigators he thought everyone was gone when the explosion happened, Montanez said. Firefighters also noted their were no vehicles parked at the residence.

An arson K9 unit detected multiple "hits" of accelerants in the rubble of the heavily-damaged house. A neighbor reported to investigators seeing a car speed off just before the explosion.

In November of 2006 Montanez said there was another arson-caused fire at the same house. That blaze was smaller, she said.

Someone had recently broken into the garage of the house that blew up, Montanez said. There were also reports of car vandalism in the neighborhood.

Firefighters were working closely with police on the investigation.

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