It took a Cobb County jury about five hours of deliberation to find 20-year-old Matthew Frederick Wilkins guilty in the Jan. 19, 2008, slaying of Marlisa Wells.
Prosecutors say Wilkins cornered his girlfriend in a basement bathroom, where he stabbed her repeatedly, slammed her head into a toilet tank and drove a fork into her back.
The girl's grandparents found Wells dead in their home after returning from a friend's funeral.
Wells believed she was pregnant at the time of her death. However, an autopsy revealed she was not.