A fire that killed 10 people at a group home for the elderly and mentally ill could have been caused by faulty electrical wiring, authorities said Wednesday in ruling out arson.

However, the exact cause of Monday's fire may never be determined because the end of the building where the fire started in the attic was destroyed, state Fire Marshal Randy Cole said.

Experts said wiring in the south end of the attic of the Anderson Guest House had been improperly spliced.

Nothing indicated natural gas was involved, and investigators weren't focusing on anything but the wiring, Cole said.

Deputy Chief State Fire Marshall Bill Zieres said nothing was stored in the attic. It was insulated with blown cellulose, "which can sustain a smoldering fire" and contained wooden trusses that supported the roof.

Investigators believe the fire started in the northwest corner of the attic and smoldered for an undetermined amount of time before breaking through the ceiling.

The north end of the one-story, cinder block structure housed a living room with a large-screen TV and some resident bedrooms, state patrol Sgt. Jason Clark said Wednesday.

Cole said the investigation was continuing, including into whether there was any negligence by the owners. He said the improperly spliced wiring was a violation of national building codes.

The community welcomed the determination that no arsonist was responsible.

"It's a relief for the town," said Bob Corcoran, mayor of the former railroad town of about 1,800 people. "We don't need that kind of people running around."

Two of the 10 victims were to be buried Wednesday afternoon — Anderson native Patricia Henson, 54, in the nearby town of Jane, and Don Schorzman, 57, in Lamar, their funeral homes said.

Questions arose about the status of the group home's owner, Robert Joseph Dupont, 62, who was convicted in 2003 of participating in a scheme to bilk Medicare.

Under state law, a convicted felon in a crime involving a health care facility is not allowed to be an "operator" or "principal" in a long-term care facility.

But in a 2004 federal bankruptcy petition, Dupont listed his occupation as executive director of the group home operator River of Life Ministries Inc., a position he said he had held for more than three years.

After The Associated Press pointed out the apparent discrepancy, Missouri Department of Health and Senior Services spokeswoman Nanci Gonder said state officials will investigate Dupont's involvement.

The agency, which licensed the group home, "would have serious concerns if an excluded individual were involved in operating the facility," Gonder said.

Dupont did not respond to repeated calls to his home and office seeking comment.

His wife, Laverne Dupont, told The Kansas City Star on Tuesday they had done nothing illegal. "We're here, and we're working with the mentally ill, and we intend to keep doing that," she said.

Shirley Brannon, who said she manages the Anderson group home, said two employees — Glen Taff, 19, and his 18-year-old wife, Amanda — "ought to be called heroes" for rescuing residents.

"He went in and out of the building three times," she said. "The fourth time, he didn't make it back. They took her out of the house screaming. She didn't want to come out. She was trying to get the rest of them," Brannon said.

The coroner said it appeared most of the rest of the victims had been asleep when the fire broke out, noting they were found dressed in bed clothes and without shoes. "It appears they all died of smoke inhalation," coroner B.J. Goodwin said.

The home had fire alarms but no sprinklers. In Missouri, only certain types of long-term care facilities are required to have comprehensive sprinkler systems and only in certain circumstances, such as those that house residents on a second floor.