The cause of death for Celina Cass is still unknown as an autopsy done on Tuesday on the missing New Hampshire girl's body didn't determine how it happened.

New Hampshire's Senior Assistant Attorney General Jane Young on Tuesday said authorities are waiting for toxicology results.

"At this time both the cause and the manner of death remain pending, pending further toxicology as well as further investigation," Young said in a press conference. "Despite those findings the attorney general's office continues to investigate her death as suspicion and a criminal investigation remains ongoing into the circumstances surrounding her death."

Young on Tuesday said a criminal investigation was launched into the 11-year-old girl's death based on a visual observation of Cass's body both in and out of the water, which was determined to be suspicious.

Young didn't say what was seen but added that because it is a criminal investigation she must withhold certain facts to "protect the integrity of that investigation if in fact, arrests are made down the road."

When reporters asked if the girls' stepfather Wendell Noyes is a person of interest in the case, Young said her office is still looking at all facets in the case.

"We are interviewing witnesses. We are looking at a number of pieces of interest, but I am not going to comment if we have a person or persons of interest," Young said.

Noyes is said to suffer from schizophrenia and was taken to a hospital after he repeatedly laid face down and rolled around in a driveway. He was released and has re-entered his community as investigators dig through the area where Cass's body was found.

It was revealed last week that Cass's stepfather has a troubled past and several allegations against him for criminal behavior. Noyes was committed to a hospital against his will in 2003 and diagnosed with schizophrenia, a mental illness characterized by delusions and hallucinations, according to reports.

ABC News reported that court records show that Noyes has been arrested for criminal trespass, criminal threatening, hindering apprehension, and violating a restraining order filed by his ex-girlfriend.

But as investigators continue to interview witnesses and they are still looking for evidence that may be in the area that may benefit the investigation, Young said.

Divers found the 11-year-old girl's body around 10:30 a.m. on Monday in the Connecticut River, one week after she went missing. Cass was last seen in her Stewartstown home on the computer on the night of July 25. The FBI has offered a $25,000 reward in the case.

Cass's father Adam Laro had pleaded for his daughter to return home safe, and upon hearing of her death he told CNN that he "can't see why somebody would want to do that to my daughter. That's the thing that puzzles me."

Young has said authorities brought Cass home but "not the way we wanted to bring her home."