Treveno Campbell, 21, is charged with shooting to death Memphis police officer Martoiya Lang in December 2012. Campbell has pleaded not guilty to first-degree murder. Authorities say Lang was killed and another officer was injured when police entered a home where drug trafficking was suspected, and a suspect inside the house opened fire with a 9mm pistol with a high-capacity magazine. Campbell was shot during the raid. Lang was a mother of four children.