A former Oak Grove High School student was sentenced to 25 years in prison in the murder of his parents.  Drew Thacker was 17 when he gunned down Ronnie and Barbara Thacker inside their home on Taylors Ferry Road on Nov. 8, 2011, prosecutors said.  Thacker was charged with capital murder, but agreed to cop a plea to the lesser charge of murder. In return, the Jefferson County district attorney's office agreed to drop the charge for his father's murder.  "This case shocks the consciousness of the court,"  Jefferson County Circuit Judge David Hodby said.