The execution of Frank Walls marked the highest number of state-sanctioned killings by a single state in more than 15 years.

Frank Athen Walls' victims include a 19-year-old junior college student who was sunbathing and a young Air Force couple who were attacked as they slept.

Frank Athen Walls, 58, was executed by lethal injection for the 1987 murder of Ann Louise Peterson, one of five killings attributed to the inmate.