A 16-year-old Michigan girl who poisoned her grandmother with morphine has been sentenced to life in prison with a chance for parole in 20 years. Kristina Adkins cried as she apologized for the slaying during Friday's sentencing. Adkins was only 13 in 2006, when 53-year-old Virginia Bentley was poisoned. Probate Judge Margaret Noe chose an adult sentence for Adkins. She could have placed her in a juvenile facility until age 21.