Why did authorities only charge Baby Grace's Parents with injury to a child?

To answer this question, the abuse that poor little Riley Ann Sawyers endured for 4 months will be admitted and used to try these two sick azz net-nerds with capitol murder. as far as Robert Sawyers, Riley's father, he did absolutely nothing wrong in this case and will not be charged with anything. Kimberly Dawn Trenor and Royce Clyde Zeigler II are the World of Warcraft playing gamer-geek pedophiles that committed this attrocious act and will burn in hell for eternity, after being d and stabbed in prison...I can't wait.