Officials said 10-year-old Antonio Rice and his sister, Patrice, 5, thechildren of Anthony and Patricia Rice, died of smoke inhalation.
Officers say no adults were at the home on 4619 Pine Trace Road, off U.S.70, whenthey arrived.
Authorities are still investigating the incident, but early reports said thechildren's mother called the home to check on them afterheading to her job at IBM in Research Triangle Park.
When she got no answer, she contacted her estranged husband and asked him tolook in on the children. When he arrived, hefound the home in northwest Raleigh engulfed in smoke.
Assistant Fire Chief Earl Fowler said the fire may have started in thekitchen around a microwave oven.
``What we found was that, inside the microwave, was clothing burnt to acrisp,'' Fowler said.
``What probably happened was that the microwave was running a little bitlonger than they thought and the material caught onfire,'' he said. ``It had two vents in it and there was a lot ofcombustibles around the microwave, setting them on fire.''
Fowler thinks the microwave generated a lot of heat, burned itself outbecause of lack of oxygen, then reignited when the elderRice broke out a window to get to his children in the house.
The body of the boy was found at the base of the stairs with soot coveringhis hands and knees. Fowler said that indicated theboy attempted to crawl out to escape the smoke. The girl was found in anupstairs bedroom.
As police were roping off the row of units which included the smoke-stainedcondo, special investigators were looking intowhy the children were at home by themselves without adult supervision.
Raleigh Police Sgt. G.S. Britt, who works with juveniles, said he would haveto review the law as it applies to the incident.State law says children 10 years old and above can stay at home alone andaren't considered at risk for a potential fire hazard.He said there is no initial evidence of abuse or neglect.
``It doesn't appear to be at this time,'' Britt said. ``This seems to be anaccidental fire. We don't have anything to show that itwas arson or anything of that nature.''
Early Monday, a family of five who moved to their Harnett County rental homeon Valentine's Day died early in a fire thatneighbors said engulfed the small, wood-frame house in minutes.
The victims were identified as Scott Moon, his wife, Christine, and theirthree children, Daniel, 7, Kelly, 5, Travis 3.
Also on Thursday, a man was killed and two women were seriously burned in afire that destroyed two mobile homes inFuquay-Varina. Preston Council, 56, died in the blaze.