A 25-year-old man will was sentenced to life in prison for decapitating his grandmother in her home in Santa Rosa. Luis Aroyo-Lopez sat silently Thursday in a Sonoma County courtroom as his family shared statements with a judge how much they suffered as a result of his brutal actions. He pleaded guilty to murder on June 4th after reaching an agreement with prosecutors. Exactly why Luis Aroyo-Lopez killed his grandmother, Elvia Aroyo-Lopez, has never been discussed in open court. He will have to serve 25 years before he eligible for parole.