CLEVELAND (AP) -- Eight children not being able to escape a house fire with a smoke detector warning led authorities to investigate whether someone set the blaze, the city fire chief said Wednesday.
''We had young, able-bodied people who we believe had a smoke detector warning and weren't able to evacuate. I think that got our attention the most,'' Chief Paul Stubbs said.
At first, investigators thought the May 21 fire the killed nine, a mother and eight children having a birthday sleepover, was accidental. Hours after about 4,000 people attended the funeral Tuesday for eight victims from the same family, their relatives were told investigators determined the fire was arson.
All nine died of smoke inhalation on the second floor of the wood-frame house. A person normally would have 3 to 4 minutes to escape in that situation, Stubbs said.
Fire Lt. Tim Corrigan, directing the installation of free smoke detectors on the street where the fire occurred, said at least one of the smoke detectors in the burned house had a battery with a charge, indicating it was in working order. Firefighters previously said they were unsure whether the smoke detectors were working.
Fire debris sent to a state lab determined an accelerant caused the fire to burn quickly, Stubbs said. He would not say what type of accelerant was used or where the fire started.
No arrests have been made, and Stubbs would not comment on whether officials had any suspects. Various people are being interviewed about the case, Stubbs said.
Mayor Jane Campbell said she met with family members of the victims Tuesday night.
''They said they had some suspicions there was something wrong, but they also said they were so sorry to hear it was intentional and none of them could imagine what would compel someone to do this, especially to children,'' she said at a news conference Wednesday.
Campbell asked for the community's help in finding the perpetrator. She stood with city safety officials next to two signs advertising phone numbers that people could call with tips.
Police were waiting for the coroner to review the case and determine whether the deaths were homicides.
Pieter Wykoff, a spokesman for the State Fire Marshal's office, declined to discuss results of tests on materials from the fire at a state lab.
Most of those who died were members of the extended Carter family. Three were burned so badly that DNA samples from family members were needed to confirm identifications.
One man escaped unharmed from the fire, which critically burned a woman whose condition was upgraded last week to fair.
''It's a tragedy. Whoever is responsible really should be buried. He should not be allowed to see the light of day after so many people died,'' said Fannie Cockfield, great-grandmother of 13-year-old victim Miles Cockfield, a friend of the children who lived in the house.
Mourners continued Wednesday to stop by a waist-high pile of flowers and stuffed animals that stretched along the front curb of the house next to the burned home.
Neta Dawson, who lives across the street, said the neighborhood was shaken up by the arson ruling.
''Whoever did it didn't have a heart,'' Dawson said.
A vague smell of charred materials still hung in the air Wednesday as firefighters installed smoke detectors provided by the Red Cross in nearby homes.
A portion of the street in front of the home remained blocked off with police tape Wednesday and an officer in a patrol car remained on duty to secure the crime scene.
Associated Press reporter Joe Milicia contributed to this story.