A Quebec man charged with first-degree murder in the death of a provincial cabinet minister's assistant won't face additional charges for the time being, but will remain in police custody until the end of the week, authorities said.

Nancy Michaud, 37, was taken from her home in Rivière-Ouelle on Friday. (CBC)

Police speculated there would be additional charges brought against Francis Proulx, 29, after the body of Nancy Michaud was found a few kilometres from her home in the small town of Rivière-Ouelle early Friday.

During a brief hearing Tuesday afternoon at the Rivière-du-Loup courthouse, Crown attorney Annie Landreville said Proulx could still face additional charges of kidnapping, confinement and robbery, but prosecutors will wait before filing formal charges.

"The investigation is not finished – it's ongoing, and we've already charged [him] with the most serious offence in the Criminal Code, which is murder," she told reporters in French outside the courtroom.

Proulx was arraigned Monday in Quebec City in the death of Michaud, a 37-year-old mother of two and community volunteer.

Francis Proulx was charged with first-degree murder on Monday. (Jean-François Desgagnés/Canadian Press)

Quebec provincial police (Sûreté du Québec, or SQ) said Michaud was snatched from her home as her two young children slept upstairs.

Her body, which showed signs of violence, was discovered in an abandoned, three-century-old house that once belonged to Proulx's grandmother.

Proulx's defence lawyer, Jean Desjardins, said he would seek bail for his client when they return to court Friday, but declined to comment on his strategy.

"We'll see a bit later," Desjardins answered when asked about bail. "You have to understand that he appeared in court today and I just became acquainted with his file a few hours ago," he said to reporters in French.

Proulx will also undergo a preliminary hearing Friday for unrelated robbery charges.

He's being held at the Rimouski Detention Centre, about 100 kilometres east of Rivière-du-Loup.

Crown prosecutor Annie Landreville says she's still waiting for the police investigation to wrap up before deciding on new charges. (Jacques Boissinot/Canadian Press)

Michaud's husband reported her missing when he arrived home after working late and discovered the children, a six-year-old and an 18-month-old, alone. Police said there were signs of a violent struggle at the house.

Police said robbery might have been a motive for the crime, and on Saturday they released a bank security video showing a masked person making a cash withdrawal early Friday morning. Money was taken from accounts belonging to Michaud and her husband.

Michaud, a former television reporter, worked as a political assistant in the constituency office of Natural Resources Minister Claude Béchard, but police have said they do not believe her slaying is related to her work.

Béchard did not attend question period at the provincial legislature on Tuesday, but stayed in his Kamouraska-Témiscouata riding where Michaud was killed.

Béchard issued a statement of sympathy late Sunday.

Defence lawyer Jean Desjardins says he'll ask for bail for his client. (Jacques Boissinot/Canadian Press)

"My thoughts and my support go out to Nancy's loved ones," he said. "She was a mother, a friend and an extremely devoted employee. On behalf of my colleagues, I would like to offer my sincere condolences to her close friends, her husband Daniel, their children and her family."

Quebec Premier Jean Charest also offered his condolences, calling her death an "inexplicable tragedy."

Public Security Minister Jacques Dupuis said while her death is an isolated incident, it offers a cautionary tale.

"Unfortunately, we cannot predict human behaviour," he said in French while speaking to reporters in Quebec City. "But we have to be vigilant when it comes to marginal behaviour."