The body of a missing 11-year-old girl from New Hampshire was found in the Connecticut River not far from her home, authorities confirmed Monday evening, as the investigation turns to how she got there.

The case has been labeled suspicious, though there is no indication so far as to who might have taken Celina Cass, who was last seen the night of July 25 in her West Stewartstown, N.H., home, where she lives with her mother and stepfather. She had been seen on her home computer but was gone the next morning.

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

Divers found Celina's body Monday morning near a hydroelectric dam that spans the Connecticut River between her hometown and Canaan, Vt., not far from the Canadian border.

Young declined to say whether there were any suspects in the girl's death. "We have made no determination on where her body was eventually put in the river," she said.

An autopsy was scheduled for Tuesday to determine the cause and manner of death. "Based on what we have seen visually, we are treating it as suspicious," Young said.

Celina's father, Adam Laro, had described his daughter to Fox News earlier as "shy but very friendly" and said he can't imagine she'd leave on her own.

"I can't picture why she would leave at night," said Laro, who was in the hospital when Celina was last seen. "She seemed to be happy where she was."

Her stepfather, Wendell Noyes, described her as a quiet girl who would not have left the family's three-story home on her own.

Young told FoxNews.com last week that authorities did not issue an Amber Alert because the case did not meet the criteria for one. Amber Alerts usually require a description of a vehicle or person the child was last with, Young said.

Town residents described Celina as a sweet, friendly child. One of Celina's best friends, 11-year-old Makayla Riendeau, said Celina loves her mother and likes her stepfather and wouldn't run away. She said Celina is very athletic, is a stickler about getting her school work done on time and loves having friends over to her house.

"She's a very good friend, and she never lets anybody down," Makayla said.

In the search for the tall, gap-toothed girl, investigators have knocked on hundreds of doors, and hundreds of fliers with her photo have been put up throughout Stewartstown and nearby communities. Law enforcement agencies have set up a command post at the local school.

The FBI has offered a $25,000 reward for information in the case, and a community member has added $5,000.

Concerned residents have passed out purple and pink ribbons and held vigils for Celina. About 80 people, many with candles in hand and tears in their eyes, gathered for a nighttime vigil in neighboring Canaan, Vt., two days after she disappeared.

"It feels like a lost section of the town," family friend Rebecca Goodrum, of nearby Beecher Falls, Vt., said at that vigil. "She was beautiful. She was the light of everything."

FoxNews.com's Cristina Corbin and the Associated Press contributed to this report.

Click for more on the disappearance of Celina Cass from MyFoxBoston.com