Prosecutors said 30-year-old Gybram Melendez of Allentown shot Carlos Rodriquez Jr. in October 2012 following an argument with the victim and another tenant of the home.
He pleaded guilty to third-degree murder last month as his trial was about to begin.
The (Easton) Express-Times says defense attorney Earl Supplee said his client had no history of violence and confrontation wasn't "something he went out looking for."
Prosecutors, however, said Tuesday the victim tried to apologize after the argument, but Melendez left the apartment on a fire escape, came back through the front door and confronted him with a gun.
Information from: The (Easton, Pa.) Express-Times, http://www.lehighvalleylive.com