The investigative team said Thursday that the deadly Aug. 11 fire at the Erie, Pennsylvania, home that included the Harris Family Daycare was an accident, caused by an electrical failure associated with the routinely used cord.
The U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives announced the 1 a.m. blaze began in the first-floor living room.
The Erie Times-News says two older boys escaped with minor injuries by crawling onto a roof. The homeowner was injured and required hospital treatment.
Investigators searched the property and electrical items were examined at a bureau laboratory in Maryland.