PHILADELPHIA — Fire officials said filling a heater with gasoline instead of kerosene caused a fire that killed seven people in a southwest Philadelphia home.

Fire Commissioner Lloyd Ayers said Monday a fire marshal's report confirms what firefighters at the scene suspected: pouring the wrong fuel in the heater touched off an "instant fire" that killed four adults and three children Friday night.

Ayers said the fire spread so fast "Those people went from looking at television to instant peril."

Three children were killed: 8-year-old Ramere Dosso, 6-year-old Mariam Dosso and 1-year-old Zyhire Wright-Teah. The other victims were 54-year-old Henry Gbokoloi, and siblings, 26-year-old Vivian Teah, 23-year-old Elliott Teah and 17-year-old Jennifer Teah.