(Tucson, AZ) -- A border patrol agent who killed a 16-year-old Mexican boy in a cross-border shooting has been found not guilty of involuntary manslaughter. Lonnie Swartz was being retried in the death of Jose Elena Rodriguez, after being acquitted of second degree murder in April. Officials say Rodriguez was throwing rocks at Swartz across the border fence dividing Arizona and Mexico in 2012. Swartz shot Rodriguez at least ten times in the back and head. His attorneys argued he shot in self-defense.