Jeff Kuhlwind, 50, who lives across the street, said he was on his computer in the front of his house when he heard screaming, "Help! Help me!"
He said he called 911, ran outside and saw "massive flames" shooting from a second-floor window, along with a woman screaming for help.
Kuhlwind and several other neighbors ran up to the front of the house, and he was about to go inside when he saw flames shooting out the front window and was forced away.
"Nobody was getting in, there wasn't no way," he said. "It went quick, really, really quick."
Investigators were looking at a wood-burning stove in the home's kitchen as a potential cause, though Chief March said it was only one among several possibilities. A family friend, Keith Wykle — who had lit the stove shortly before the fire broke out — said he'd lit it many times previously and never had a problem with it. He said he had been hanging out with his friend Eric Brown earlier in the evening.
March also said there was no immediate evidence of smoke detectors in the home.
The upper two floors of the three-story home were charred and the rear of the building appeared to have sustained heavy damage, with several of the walls knocked out. Furniture and other debris sat on the front sidewalk.
Crews from all the city's fire companies responded to the blaze and March said investigators had to proceed carefully through the building because of the extensive amount of damage.
Neighbors were taking it hard, choking back tears as they recounted the fire and recalled the family who lived there.
"My heart's breaking for my little girl because I really don't think she understands," said Christina Groves, who lives behind the house. "They were her best friends ... and I don't think she understands the true meaning that her friends aren't coming back."