A jury in Saguenay, Que., has found Cathie Gauthier guilty in the premeditated killings of her three children as part of a New Year's Eve murder-suicide pact with her husband.

Cathie Gauthier, left, is escorted to the courthouse on Oct.7 in Saguenay, Que. (Canadian Press)

The verdict was delivered Saturday, 3½ days after the jury heard the judge's instructions in Quebec Superior Court and began deliberations.

Gauthier was charged with three counts of first-degree murder after the bodies of her children and husband were found in the family's rented bungalow last Jan. 2 in Saguenay, about 250 kilometres north of Quebec City.

The children — Joëlle, 12, Marc-Ange, 7, and Louis-Philippe, 4 — were poisoned by a mix of Gravol anti-nausea medication and a tranquillizer.

Their father, Marc Laliberté, died of blood loss due to a cut on his wrist, worsened by a heart condition.

The family was suffering from financial troubles and had filed for bankruptcy in October. Laliberté had not worked in months and Gauthier had lost a series of jobs at retail stores.

The defence argued Laliberté was responsible for the children’s deaths.

An equal participant

Gauthier, who was found with her right wrist slashed when police arrived at the home, testified she didn’t believe her husband when he told her on New Year's Eve the family was “going on a trip and never coming back.”

Crown prosecutor Sonia Rouleau had argued that Gauthier, 35, was an equal participant with her husband in the murder-suicide plan for several reasons.

Rouleau said Gauthier bought doses of the prescription medication found in her children's blood.

The lawyer also showed the jury several letters she described as "vindictive" and said that, in them, Gauthier tried to make relatives, former employers and a best friend feel guilty for the tragic events that would unfold on Dec. 31, 2008.

Gauthier wrote that her family would be dead by the time people read the letters. She testified her husband dictated the letters on the same day the killings took place.

Gauthier had told the court she felt like she was "out of her body" and "totally disconnected" while writing the letters.

The Crown had questioned why Gauthier took a hot bath upon waking up with her wrist slashed — and her children motionless — instead of immediately calling 911.

Gauthier faces a life sentence with no chance of parole for 25 years.