Ulysses Wiggins was convicted in the fatal shooting of 24-year-old Catherine Walker two years ago.
Witnesses say Walker was an innocent bystander, killed during an argument between Wiggins and his ex-girlfriend.
Police say the bullet struck the woman in her left shoulder and right upper back.
Wiggins alleges Walker got in the middle of the dispute. Police say there was gun powder residue on Walker's wound indicating a close-range shot. Witnesses say Walker was mentally challenged.
Police testified that Wiggins fled the scene after the shooting but was arrested a short time later.