Police in Indianapolis say a 69-year-old man is the second person to die of injuries suffered in a sword fight with a younger relative.
Authorities say Adolf Stegbauer died Monday, four days after an argument escalated into the fight with 39-year-old Christopher Rondeau.
Police said Stegbauer's death had been ruled a homicide.
Stegbauer's 77-year-old sister-in-law, Franziska, was fatally stabbed while trying to break up the fight.
Rondeau, who is her grandson, also was wounded.
Rondeau was being held on preliminary charges of attempted murder and police Lt. Dawn Snyder said amended charges were being prepared.
Investigators said one of the weapons was a World War II-era Japanese sword with a thin blade.