County prosecutors say no charges will be filed against 25-year-old Raquel E. Martinez in the death of 42-year-old Jose Luis Mucio-Olayo.
Deputies responding to a fight near Murtaugh found two men with gunshot wounds, an uninjured woman and a car in flames.
An investigation determined a dispute developed among Mucio-Olayo, 28-year-old Javier Carbajal-Galvan and the woman.
Mucio-Olayo fired a small-caliber rifle at Carbajal-Galvan at close range, striking him several times. He then fired at Martinez.
Prosecutors say Martinez returned fire with a large-caliber handgun to defend herself and Carbajal-Galvan, fatally wounding Mucio-Olayo. A round injured another man who drove himself to the hospital before deputies arrived.