The death of a 12-year-old Nova Scotia girl who went missing in late January is being treated as a homicide. But while police won't say how Karissa Boudreau died, they say they're confident her murder was an isolated incident.

The body of the Grade 6 student was found near Bridgewater, N.S. last Saturday, although police only confirmed her identity after an autopsy was conducted Wednesday in Halifax. Because the body was found in sub-zero conditions, it took several days before it was in a suitable state for the procedure, police said.

She was eventually identified using dental records, police said.

Boudreau disappeared on Jan. 27 after having an argument in the parking lot of a Bridgewater shopping mall.

Penny Boudreau said she went into a grocery store after the argument and returned to her car 10 minutes later to find her daughter was missing.

Last Saturday, police said they had found the body of a "young Caucasian female" on the banks of the LaHave River, just outside the town of Bridgewater.

Following an agonizing wait and two tearful public pleas for their daughter to come home, Boudreau's parents were notified of their daughter's death at 9:30 a.m. Thursday morning.

Representatives from both the RCMP and Bridgewater Police Services spoke to media Thursday. Sgt. John Collyer, of the Bridgewater Police Service, said police have no suspects at this time.

"We're putting all our efforts into trying to bring this to a successful resolution," Collyer told reporters gathered in Chester, N.S. "The investigators feel this is an isolated incident and I would suggest Bridgewater is a pretty safe community most of the time."

CTV's Denelle Balfour reported the police say they know how Boudreau died but are keeping quiet to maintain the integrity of the investigation, which is being conducted by a combined team of Bridgewater police and RCMP officers.

Sheldon MacLeod, news director of Bridgewater radio station CKBW, said the worst part for the community is that they don't know what happened.

"A tough part of the story (is) the lack of information," he told CTV. "(The news of her murder opened) another can of worms. Is someone responsible of the death of a young girl in our community?"

The principal of Bridgewater Elementary School, where Boudreau was a student, said he sent a letter home with all the students explaining the situation to their parents and warning them to be doubly careful of their safety.

"We're coping," he told CTV Atlantic's Leah Cross. "As today winds down it's getting tougher and tougher."

By Thursday afternoon, the area where Boudreau was found was covered in teddy bears and flowers and local parents were left reeling about the safety of their own children in the wake of her killing.

"Until I know exactly what happened, I'm not letting (my children) out of my sight," one mother told CTV Atlantic.

Police are advising Bridgewater residents to be cautious, vigilant and know where loved ones are at all times

With files from CTV's Denelle Balfour and Leah Cross