Celina Cass' biological father, Adam Laro, told a Boston news station that the little girl's stepfather Wendell Noyes behaved strangely after the little girl disappeared.  Celina, 11, was found dead by divers in the Connecticut River.

"Things started to become different...something was weird -- something was strange but I couldn't place it. Something was strange," Laro told WHDH-TV.

Noyes, who suffers from schizophrenia, was taken to the hospital by ambulance Monday morning after he repeatedly rolled around in a driveway.   He has since been released.

Noyes was forcibly committed to a hospital and diagnosed with schizophrenia in 2003, ABC News reported. ABC also obtained court records that reveal Noyes' arrest record for violating a restraining order and threatening his ex-girlfriend.

An autopsy was performed Tuesday but results were inconclusive and cause of death was not determined.   Authorities said that the death was "suspicious" although no signs of struggle were found in her West Stewartstown, N.H. home.

Celina Cass was last seen July 25 at 9 p.m. in her bedroom using her computer in her West Stewartstown, N.H. home, authorities said.

"We have brought Celina home, obviously not the way we wanted to bring her home," said New Hampshire Senior Assistant Attorney General Jane Young Monday.

Adam Laro, Celina's father, told Fox News that the girl was "shy but very friendly" and that she would not leave on her own.  "I can't picture why she would leave at night," said Laro.

Most of Noyes' Facebook friends are young women from different parts of the country and some appear to be models.  Noyes reportedly posted flirtatious comments on some of the girls' profiles as recently as last month.

Assistant Attorney General Jane Young said in a news conference Tuesday that toxicology tests will likely shed more light.