A 7-year-old girl and her father died in a house fire near Mukilteo early Thursday.

South County Fire crews responded to the fire in a one-story home, The Daily Herald reported.

“The rapidly moving fire had already heavily damaged the house,” South County Fire in Everett said in a statement. “Flames were through the roof and visible in most of the windows. The floor was nearing the point of collapse. Firefighters initially were unsure if anyone was inside.”

The bodies of the girl and her father were found after the fire had been knocked down, South County Fire spokesperson Leslie Hynes told The Daily Herald.

The fire is still being investigated.