It has emerged that police investigating the mysterious disappearance and death of 11-year-old New-Hampshire girl Celina Cass have questioned her stepfather Wendell Noyes, who was seen rolling around in the driveway hours before her body was fished out of Connecticut river.

Stepfather Noyes, who had been medically discharged from the Air Force on grounds of mental illness, was "uncooperative" when the police questioned him, WBZ-TV reported, citing a source.

Meanwhile, police are waiting for the result of an autopsy on Celina's body to advance their investigation into her death. They can’t confirm or deny if the death was a kidnap and murder, or just an accidental drowning. The autopsy has been performed, but the results have not been released yet, according to WBZ-TV.

Police have a long way to go piecing together what happened between the July 25 night when Celina was last spotted in her bedroom, playing on the computer, and the fishing out of her body a week later from near a hydroelectric dam on the Connecticut River between Stewartstown and the town of Canaan, Vermont.

"We continue to investigate this case ... We are looking at all facets of the investigation and that includes where she was last seen," Senior Assistant Attorney General Jane Young said.

Police have not identified anyone as a suspect as yet. Nor have they been able to determine where in the rive her body was eventually placed. Young declined to reveal if police have detected early signs leading to the person behind her disappearance and death. There are no "persons of interest" at the moment, and no arrests have been made.

An emotional candlelight vigil was held in the West Stewartstown town, which was attended by hundreds of people.

Celina's family spoke to the media to thank everyone who was involved in the search operation. "Fish and game, Attorney General, FBI, they were all there when we needed them ... The news media was very good to us, very good to us and they really helped out as much as they could. All we're looking for now is answers," said Walter Laro, Celina's grandfather.

Meanwhile, a lot more about Noyell has emerged, most of it unflattering. The 47-year-old, who had been diagnosed with schizophrenia, had been taken to a hospital by an ambulance on Monday after a bout of bizarre behavior. However, it was reported on Tuesday that he had been spotted in town, buying cigarettes.

Noyes had been arrested in 2003 for threatening an ex-girlfriend and was involuntarily institutionalized. But in this case, he was declared unfit to stand trial owing to his mental illness. However, the judge had noted that his mental illness posed "a potentially serious likelihood of danger to himself and others."

Finding Celina's body in a river half a mile from her home on Monday after a massive air, land and water-borne search operation conducted by the local police and the FBI, has helped investigators close one chapter in the case. But now they are bedeviled with more serious questions. How did the girl disappear and meet with mysterious death? Was she abducted and killed? Was a child predator at work? Or was it an accidental death by drowning? And above all, if it was a murder, who killed her? All that the police have confirmed for now is that Celina's death is "suspicious".

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