OKLAHOMA CITY (AP) -- A house fire that killed six people was human generated, according to Oklahoma City fire investigators.
While the fire has been called ``human generated'' officials haven't said it's an arson case.
``We can't say it is arson because arson requires a willful and malicious intent,'' said Fire Maj. Brian Stanaland.
The fire killed Oliver ``Jack'' and Connie Somers-Wilder, ages 63 and 48, respectively, and their children, Daneel, 19; Leisylle, 17; and Aimy, 12, died in the fire, along with neighbor Karla Hayes, 15.
All six were trapped inside the home when it burned Sept. 26.
The fire, considered one of the most deadly house fires in Oklahoma City history, remains under investigation, Stanaland said.
Stanaland refused to say whether investigators have a suspect. He also refused to discuss reasons for the delay.
April Coberly, an 18-year-old neighbor of the family, was questioned by investigators and given a polygraph Sept. 30.
Her mother, Pat Coberly, said April Coberly was pressured to say she placed a burning box containing dog feces on the Somers-Wilders' porch.
Her mother said Monday that investigators have not told her whether her daughter passed the polygraph test. April Coberly has moved from the home, Pat Coberly said.
``She can't handle looking at that house and her four friends are not here,'' Pat Coberly said. ``She said, 'It is really starting to bother me.'''
The mother said she doesn't think her daughter started the fire.
Investigators are working with the district attorney.
``Investigation into fires is an extremely difficult process,'' Stanaland said. ``First, the actual fire destroys a lot of evidence.''