40-year-old Officer Moses Walker Jr. was killed in an early-morning robbery attempt in August 2012.
A co-defendant testified this week that Walker looked like a college student and an easy target. He was dressed in shorts and carrying a backpack.
Walker instead reached for a weapon and was shot by his assailant.
25-year-old Rafael Jones, who prosecutors say was the gunman, was convicted Thursday of first-degree murder in a non-jury trial that spared him a possible death sentence.
The conviction carries a mandatory life sentence.
21-year-old co-defendant Chauncier McFarland pleaded guilty to third-degree murder and faces a 20- to 40-year prison sentence.