leanna norris , 25 , of auburn , plied two-year-old loh grenada with benedryl to make her sleep before by covering her mouth and nose with duct tape and a blanket , a court heard .
the body was found in the front seat of her car in stetson , maine , on june 24 , 2013 .
general deb cashman said norrishad committed the murder to stop her ex-boyfriend , the father of her child , dating other women .