Roxanne Buck was convicted Friday morning on charges of murder and tampering with evidence for the March stabbing death of her 21-year-old Stow housemate. She is scheduled for sentencing at 11 a.m. Tuesday in Summit County Common Pleas Judge Mary Margaret Rowlands’ courtroom.Buck, 45, is facing life in prison. As the verdicts were being announced, she sat next to defense attorney Scott Rilley, staring straight ahead at the bench, and dropped her head when the decision came.On the night of March 15, after Michelle Johnson’s mother had tried and failed to contact her, authorities found Johnson’s body in a rickety shed behind the garage at a Maplepark Road duplex in Stow.Buck had lived there in a first-floor bedroom with Johnson and her mother, Diane Johnson, whom Buck had known for more than 20 years.Minutes after the verdicts, Diane Johnson said she was happy with the conviction as she stood among 10 family members and friends in a courtroom hallway.“She was guilty from Day 1.