A mother has pleaded guilty to murdering her only child after being told by her boyfriend: 'It's her or me'. Penny Boudreau strangled her 12-year-old daughter Karissa in a twisted bid to stop her boyfriend from ending their affair. The heartless mother ignored her terrified daughter's cries of 'Mummy, don't!' as she pinned her to the ground and wrapped a rope around her neck, prosecutor Paul Scovi told a Canadian court.