An accelerant doused in the living room and basement started a fire that killed seven members of a family who had moved to this southwest Chicago suburb a year ago from New York.
Dogs picked up the odor of the accelerant, which has yet to be identified, Police Chief Bill Kujawa said Sunday.
He refused to discuss a motive or say whether there were any suspects.
The blaze started in the living room shortly after 3 a.m. Saturday and quickly spread through the split-level house.
The dead were identified as Abdulla Yaffai, 62, and his six children, whose surnames were Mohamed: Quasam, 3; Gaze, 5; Hanan, 9; Zain, 13; Aneece, 14; and Mohamed, 16.