William Fuller confessed to being the gunman and pleaded guilty Wednesday to murder. The 21-year-old Fuller faces up to 99 years in prison when he's sentenced Nov. 8.
Fuller originally was charged with capital murder over the 2010 shooting death of Pauletta Burleson, but cooperated with the prosecution.
Pastor Tracy Burleson last month was convicted of capital murder and sentenced to life in prison for his role in the slaying. Jurors last week found the preacher's mistress, Tyonne Palmer, guilty of murder for helping arrange the killing and sentenced her to seven years in prison.
Fuller said he was promised some of the victim's insurance benefits.