An autopsy was scheduled for Tuesday to determine the cause of death of an 11-year-old New Hampshire girl, whose body was found in the Connecticut River near her home.

Dive teams found the body of Celina Cass around 10:30 a.m. on Monday near a hydroelectric dam.  Authorities said they consider the girl's death suspicious after seeing the condition of her body.

New Hampshire Assistant Attorney General Jane Young said, "We are treating it as a criminal investigation based on what we know at this juncture."

The girl vanished on July 25 from her bedroom, where she was last seen playing computer games.

Young wouldn't say whether police had identified any suspects, but said they were interviewing witnesses, according to The Boston Globe.