OKLAHOMA CITY (AP) -- More than two-dozen interviews have brought fire investigators no closer to determining what caused a blaze that killed six people last fall, officials said Monday.
All leads in the Sept. 26 fire in southeast Oklahoma City have been investigated, fire investigator Homer Jones said.
``We haven't come up with anything,'' Jones told The Oklahoman.
Officials have some circumstantial evidence, but not enough to make an arrest, said Jones, the head of fire investigations.
Oliver Somers-Wilder, 63, Connie Somers-Wilder, 48, and their children, Daneel, 19; Leisylle, 17; and Aimy, 12, died in the fire, along with neighbor Karla Hayes, 15.
The blaze started on the front porch of the house, which had windows protected by burglar bars, Jones said.
The family was preparing to move and had stacked boxes blocking all exits except the front door.
The fire hasn't been ruled as arson because investigators can't prove there was a willful or malicious intent, Jones said. It is being called ``human generated.''
``The case will be open until we get a break of some type to find out exactly what happened,'' Jones said.
April Coberly, an 18-year-old neighbor, was questioned and given a polygraph test by investigators.
Pat Coberly, the girl's mother, said investigators tried to scare her daughter into saying she placed a burning box containing dog feces on her neighbor's porch, starting the deadly fire.
Jones said they couldn't confirm the fire started from the burning box.
``We looked at several avenues, and that was one we did pursue because we got information that that was a possibility,'' Jones said. ``We can't confirm that there was ever any merit to that.''
Jones said April Coberly and her mother were two of at least 25 people who were interviewed as part of the investigation.
The polygraph was used to clarify inconsistencies in April Coberly's story, Jones said.
Pat Coberly said neither she nor her daughter have heard from fire investigators since the polygraph. April Coberly has moved from the neighborhood.
As for the probe, Jones called the lack of leads frustrating.
``You want to solve all of them,'' Jones said. ``When burn victims and fire fatalities are involved, you really want to solve it.''