A man who jumped out of a second-floor window of his burning house and faces murder and arson charges in the deaths of his wife and four children has regained consciousness and talked with investigators, officials said Monday.

Investigators wouldn't reveal details of the interviews with Michel Veillette, who remained hospitalized while authorities tried to sort out the Friday night tragedy in this Cincinnati suburb.

Veillette, 34, was stabbed, but authorities wouldn't discuss the extent of his injuries or a possible motive. His wife, Nadya Ferrari-Veillette, 33, died of stab wounds. She and the couple's 4-year-old son, Vincent, were found dead at the scene; the other children died at a hospital.

"We are involved in a very complex investigation," Police Chief Ronald Ferrell said. Investigators spoke to Veillette at least twice, once for more than an hour, he said.

Investigators were also talking to relatives and friends of the family in their native Canada. The state fire marshal's office and crime lab investigators were still combing the house Monday, and authorities awaited final autopsy reports.

A gas can was found on the second floor of the home, the state fire marshal's office said. Vincent was probably killed by carbon monoxide poisoning due to smoke inhalation.

None of the children had been stabbed, police said earlier.

Veillette faces four counts of aggravated murder, one count of murder and one count of aggravated arson. He was in serious but stable condition over the weekend, but officials had no update on his condition Monday.

"Our goal right now is to bring someone to justice for what has happened to these four innocent children and their mother," Warren County Prosecutor Rachel Hutzel said at a news conference. She said she did not know whether Veillette had hired an attorney.

The other children were identified as Marguerite, 8, and twins Mia and Jacob, 3.

Neighbors said they often saw Marguerite walking to and from the bus stop accompanied by her mother and siblings. Neighbors told The Cincinnati Enquirer that the family moved to the upscale neighborhood in Mason about 18 months ago.

Veillette traveled frequently to Troy, Ohio, and Windsor, Ontario, for his job designing auto engines and was home only a few days a month, neighbors said.

Ferrari-Veillette, who worked part-time at a cafe, often volunteered for cafeteria duty at her older daughter's school.