Case of Celina Cass, 11, found dead in a river, is "suspicious" (VIDEO)

The death of Celina Cass, the 11-year-old New Hampshire girl who went missing on July 25 and was found dead in a river half a mile from her home on Monday, is being treated as "suspicious."

New Hampshire Assistant Attorney General Jane Young, addressing the media after Cass was found near a hydroelectric plant outside Stewartstown, New Hampshire, said the death would be treated as a criminal investigation after seeing the condition of the body.

"Based on what we have seen visually we are treating it as suspicious ... She was located in the water so we are trying to determine how her body was put in the water," said Young.

The medical examiner’s office in Concord will conduct an autopsy Tuesday, the Boston Globe reports.

Cass' stepfather Wendell Noyes, an ex-Air force staff, was the focus of several media reports about her death.

Noyes was diagnosed with schizophrenia and institutionalized in 2003 after being accused of threatening an ex-girlfriend. He was declared unfit to stand trial owing to his mental illness, the International Business Times reports.

On local radio shows, comments called attention to the Facebook profile of Noyes which they referred to as "creepy." 

Cass was last seen a week ago in her room at her home in West Stewartstown. Her biological father, Adam Laro, on Sunday pleaded for her safe return, CNN reports.

Laro, in hospital when Celina went missing, sent her a message, saying he was "wondering where my daughter is" and hoping she was safe.

"Whenever you want to come home, Celina, Daddy will be here waiting for you," Laro said.

Cass' half-brother, also named Adam Laro, told the Globe that the family was devastated by the news and had no idea what might have happened.

“She was a beautiful girl,’’ Laro, 21, reportedly said, describing Cass as a friendly girl who seemed happy at home.

“We just don’t know,’’ he said. “It’s all we can think about, but we just don’t know.’’