Police in Nova Scotia say the mother of 12-year-old Karissa Boudreau has been charged with her daughter's murder, four months after the girl's body was found.

Officials told a news conference held Saturday in Bridgewater that they arrested Penny Boudreau, 33, in Halifax on Friday.

"She will answer to the charge of first-degree murder," said RCMP Supt. Blair McKnight, the officer in charge of criminal investigations in the province.

Bridgewater Police Chief Brent Crowhurst said there are no other suspects wanted in connection with Boudreau's death.

"Investigators feel confident that there is only one person responsible for this homicide," he said. "We do not expect anyone else to be charged in this case."

Penny Boudreau reported her daughter missing on Jan. 27 after she apparently went missing in a supermarket parking lot. On Feb. 9, a passerby found Karissa's frozen body on the nearby banks of the LaHave River.

After an autopsy was performed on Karissa's body, police said they were treating her death as a homicide. They did not release any details about how the girl was killed.

The city of 8,000, about a 90-minute drive southwest of Halifax, hadn't recorded a homicide since 1993. Residents were stunned by the news of the girl's death.

"This is Bridgewater, Nova Scotia. Nothing like this has ever happened," said resident Candice Hubley.

Mayor Carrol Publicover said news of Boudreau's arrest would come as a relief to his town.

"As time went on, while police assured people it was an isolated incident . . . people started to wonder what the circumstances might have been," he said. "The arrest today is hopefully the beginning of the end of this whole situation and people will eventually be able to bring closure to it."

McKnight said Penny Boudreau will appear in provincial court in Bridgewater on Monday.

The mother's account

Penny Boudreau had said she argued with Karissa on the day she went missing. She told police she had left her daughter in her vehicle before going to the supermarket. Upon returning, she discovered the Grade 6 student was gone.

Two days later, she made an emotional plea to the media and public to help her get her daughter back.

"I'm trying not to think the worst. It's plain and simple hell. Not knowing where your kids are is horrible," she said at the news conference.

Police had arrested and released two suspects in the days following the discovery of Karissa's body. While they told the tight-knit community to be vigilant, police had also said that they were treating Karissa's murder as an isolated incident.

At Karissa's funeral, Rev. Perry Ingersoll had praised her friendly personality, "winning smile" and love for animals. Her teachers and friends described Karissa as a typical youngster who liked to sing and listen to pop music.

With files from The Canadian Press