Penny Patricia Boudreau pleaded guilty to second-degree murder Friday in a Bridgewater courtroom. She admitted strangling her only child because the 12 year old was getting in the way of her relationship with her boyfriend, Vernon Macumber.

 Although the plea bargain reached by Crown and defence was for second-degree murder, the facts read in court revealed Ms Boudreau thought about the killing for days, carried it out, discarded her daughter's body and covered up her crime.

 "Surely, Penny Boudreau, you can never call yourself mother in conjunction with Karissa's name again," Justice Margaret Stewart concluded.

 Ms Boudreau, 34, entered the courtroom dressed in a black T-shirt and jeans, sniffling and wiping tears. She sat through most of the proceedings, turning her chair so her back was to the courtroom gallery, occasionally rocking back and forth, using tissues offered by the deputy sheriffs who surrounded her.

 She stood three times - to re-elect her method of trial and enter a guilty plea, to answer a series of questions from the judge to confirm that guilty plea, and when she was sentenced to life in prison with no chance of parole for 20 years.

 According to an agreed statement of facts which Crown attorney Paul Scovil read to the court, Ms Boudreau and Mr. Macumber were having issues they blamed on Karissa in January 2008. Mr. Macumber gave Ms Boudreau an ultimatum to choose between him and her daughter.

 On the afternoon of January 27, Ms Boudreau took Karissa for a drive. She stopped at the Sobeys parking lot around 5:30 p.m., bought juice and bacon, and called Mr. Macumber indicating Karissa was not in the car when she left the store.

 She then took a piece of twine from the trunk, put it in her pocket and got back in the car with her daughter.

 Ms Boudreau drove around waiting for it to get dark. Karissa kept asking to get out of the car and her mother finally stopped on the William Hebb Road just outside town and told her to get out. She tackled the girl, who fell on her back with her hands pinned beneath her.

 Karissa said "Mommy, don't" as her mother knelt on her chest, wrapped the twine around the girl's neck and pulled with all her strength.

 Sobs could be heard in the courtroom as Mr. Scovil said the dying girl struggled to free herself, digging her hands into the ground. Ms Boudreau kept pulling the rope tight as Karissa's eyes bulged and she heaved for air until she stopped breathing.

 The woman dragged Karissa's body back into the passenger's side of the car. She put the twine in an empty coffee cup and threw it away at the High Street Tim Hortons, then dumped Karissa's body over the riverbank just outside town where it was found February 9.

 As she yanked Karissa out of the car, the girl's jeans and pink Winnie the Pooh panties were pulled down. Ms Boudreau left her like that, thinking it would make people believe the girl had been sexually assaulted. She knew it was going to snow and didn't think the child's body would be found for some time.

 She threw Karissa's black hoodie, black vest and one of her pink shoes in a garbage can by the Bridgewater swimming pool and went home. The other shoe had been lost on the William Hebb Road. It would be found two days later and turned in to authorities.

 Ms Boudreau then called the police, family, friends and Karissa's teachers to tell them she was missing.

 She maintained that story until June, when police tricked her into confessing her crime.

 Investigators had suspected Ms Boudreau from the outset, but two days after Karissa's body was found, on February 11, they received a report of a disturbance at the apartment she shared with Mr. Macumber. People in the apartment below heard the couple arguing and Mr. Macumber saying he was disgusted with her, repeatedly asking "Penn, how could you do this?"

 Police arrested the pair for Karissa's murder on February 14, planting an undercover officer in Mr. Macumber's cell. They bonded and the undercover officer continued to meet with Mr. Macumber over the next few months in the guise of giving him work for a crime syndicate.

 After Ms Boudreau and Mr. Macumber moved to Halifax in April, Mr. Macumber told the undercover officer he'd had nothing to do with Karissa's murder, but suspected Ms Boudreau. He said he was still living with her so she would not implicate him in the crime.

 Investigators then drew Ms Boudreau into the sting. In May, she told them she wished the police exhibit vault would burn down or blow up. They used that information to introduce her to an undercover officer posing as a crime boss who could make her problem go away.

 He convinced her to tell him the details of what happened to her daughter so he could help her. She confessed everything on June 11, even travelling back to Bridgewater to show undercover officers, still posing as criminals, where she had killed Karissa.

 Mr. Scovil said Ms Boudreau was "jovial" as she described the crime. She told the officer "she would do anything for Vernon and the thought of losing him was harder than the thought of losing her daughter."

 Police arrested her three days later. Confronted with a video of the meeting, she confessed to murder.

 Mr. Scovil told the court Ms Boudreau had lots of options other than killing the cheerful, bubbly 12 year old.

 "She should be here as a Grade 7 student at Bridgewater. She should be going to dances. She should be going through exams like other kids, and having fun," the Crown attorney said.

 Fellow prosecutor Denise Smith told the judge the Crown agreed to take a plea to second-degree murder to save Karissa's family the anguish of a trial, but that doesn't lessen Ms Boudreau's moral culpability.

 "A mother killing her child is an incomprehensible crime," Ms Smith said. "Karissa was failed by the one person who should have protected her."

 Second-degree murder carries a mandatory sentence of life in prison.

 Justice Stewart followed a joint recommendation from Crown and defence lawyers in giving Ms Boudreau no chance of parole for 20 years. She said there is no evidence of mental illness, drug abuse, anger management issues or an inability to think rationally to explain the crime.

 "End remorse flows from having an overwhelming case against her," Justice Stewart said. "A young, vibrant life full of promise was terminated for a reason no more significant than Penny Boudreau's selfish desire to guarantee a love life that had no room for a child."

 Ms Boudreau will be eligible to apply for parole on June 14, 2028, two decades after the date of her arrest.

 Under Canada's faint-hope clause, she can ask a jury to consider an early release application in 15 years. If the jury agrees, she can apply for release.

 The National Parole Board will determine if she will be released based on her risk to society. If freed, she'll remain on parole for the rest of her life. Parole may be revoked and offenders returned to prison if they violate their release conditions or commit a new offence.