A B.C. woman convicted in the death of her eight-year-old daughter will not be eligible for parole for at least 15 years.

Lisa Batstone learned her fate in a New Westminster courtroom Tuesday, nearly three months after being found guilty of second-degree murder.

Reading her verdict, Justice Catherine Murray said Batstone's decision to smother her daughter, Teagan, in 2014 was "deliberate, systematic, focused, purposeful and goal-directed."

"This decision must send a message that children cannot be used as pawns in marital disputes," she said.

Batstone will serve at least 15 years in prison before facing a parole board for possible release. She's also been given a lifetime ban on firearms.

The Crown asked that Batstone serve 16 to 18 years of her mandatory prison sentence, while the defence asked for 10 to 12 years.

"Miss Batstone is obviously upset and disappointed with the verdict. The sentence is obviously at the higher end of the range," said Eric Gottardi, Batstone's defence lawyer.

Reviewing the reasons for her decision, Murray said Batstone showed signs of borderline personality disorder and "projected" her issues on Teagan.

"A mother killing her own child is an extreme breach of trust," she said.

Teagan's body was found in the back of a car in South Surrey on Dec. 10, 2014.

During the trial, prosecutors told the court the child had been smothered in her sleep. The Crown argued Batstone took deliberate actions and intended to cause her daughter's death, saying the act was motivated in part by resentment toward her ex-husband Gabe.

"I wanted to die and I didn't want to abandon her with him," Batstone told police in a recorded interview after her daughter's death.

Batstone's defence did not dispute the girl's cause of death, but asked the judge to consider a verdict of manslaughter instead of second-degree murder. Her lawyers said Batstone's mental state at the time was unclear, and that she could have been affected by stress, mental disorders, and consumption of alcohol and prescription drugs.

"We feel the mental health system failed Miss Batstone, it failed her daughter," said Gottardi.

In her ruling in June, Murray told the court Batstone put a plastic bag over Teagan's mouth and nose to suffocate her daughter.

"The killing was deliberate. It involved some choices and decisions. It involved effort," Murray said.

The 8-year-old's family says their heartbreak is far from over.

"I think closure is but of a fiction for those who suffer from this kind of trauma," said Gabe Batstone, Teagan's father.

He said no amount of time behind bars would undo the tragedy, but that he respected the judge's decision.

"Nothing is going to bring Teagan back. That's the reality. We live without out our beautiful little girl for the rest of our lives," Gabe said.

Gabe and his wife Stephanie have created an advocacy organization to help prevent violence against children called Teagan's Voice.

"If we don't talk about this, nothing is ever going to change. We hope if we can save just one child, get one child to safety through talking about this, then our pain is worth it," he told CTV News.

Lisa Batstone has 30 days to file a notice of appeal. Her lawyer said she was too emotional Tuesday to make a decision on the matter.

Read back through live coverage from Regan Hasegawa in court.