Spencer Carr was described by those who knew him as a happy 8-year-old boy who ran around his Center Line neighborhood with his best friend and classmate from next door.Spencer and a 37-year-old Detroit woman with a form of Down syndrome died in separate house fires Thursday morning. Three others were burned in the two fires.Spencer died when a fire that began about 4:30 a.m. ripped through his family’s two-story frame home in the 8100 block of Harding near 10 Mile and Van Dyke. His mother, Nola Carr, and his 14-year-old sister, Tanya Carr, suffered second-degree burns to their upper bodies before escaping the blaze through a second-floor window, said Nicholas Chakur, interim director of the Center Line Department of Public Safety.The pair were treated at Detroit Receiving Hospital and later released. David Carr, Spencer’s father and a Chrysler employee, was at work when he learned of the fire and rushed to the scene. Investigators have yet to determine the cause of the fire, in large part because the blaze devastated the two-story home.Recovery of Spencer’s body and an investigation into the cause of the fire was held up for hours while the stability of the structure was checked. Heat from the flames caused the structure to sag and lean.Tammy Isbill, who said she has lived across the street from the Carr family for 15 years, said she heard the woman screaming to her daughter that they needed to find Spencer.Meanwhile, on the west side of Detroit, a fire that killed a 37-year-old woman in the 7700 block of Smart was an accident likely caused by a burning candle, a city arson official said.The fire occurred about 9:15 a.m. and was confined to the home’s living room and front porch, Simmons said.Firefighters found a candle next to the couch, where they also found the woman’s body. Simmons said the woman’s father was in the back of the house when the fire started. He suffered first- and second-degree burns on his hands and head after trying to save his daughter. He eventually was overcome by smoke and was forced to exit the burning home.By DAN CORTEZ, FreePress.comStaff writer Naomi R. Patton contributed to this report.