Penny Patricia Boudreau was born in 1974 in Ontario, Canada, and grew up in Clark's Harbour, Nova Scotia. She led a seemingly ordinary life, working and raising her daughter, Karissa Boudreau. At the time of the crime, Boudreau lived in Bridgewater, Nova Scotia, with her boyfriend, Vernon Macumber. The relationship between Penny and her daughter was reportedly strained, with frequent arguments and conflicts. Penny claimed that Macumber gave her an ultimatum: either her daughter had to leave, or he would end their relationship. However, Macumber denied this, stating that he had asked them to address their issues but did not imply any harm toward Karissa.

On January 27, 2008, Penny Boudreau reported her 12-year-old daughter, Karissa, missing, stating that she had vanished from her car while Penny was shopping at a grocery store. The community rallied together, conducting search efforts to locate the missing girl. Two weeks later, on February 9, Karissa's body was discovered under the snow on a bank of the LaHave River near Bridgewater. An autopsy revealed that she had been strangled to death.

The investigation into Karissa's disappearance and death led authorities to suspect Penny. In June 2008, following an undercover operation, Penny confessed to murdering her daughter, stating that she believed it would save her relationship with her boyfriend. She detailed how she had driven Karissa to the outskirts of Bridgewater, tackled her to the ground, and strangled her with a piece of twine while kneeling on her chest.

In July 2008, Penny Boudreau pleaded guilty to second-degree murder and was sentenced to life imprisonment with no chance of parole for 20 years. The case shocked the nation, as the community struggled to comprehend how a mother could commit such a heinous act against her own child.