Police say they were already responding to a disturbance call at the house in the area of Brawley and Princeton when they got reports of the shooting.
Action News has learned the man shot was critically injured and died of his injuries overnight.
Investigators say a 48-year-old suspect was standing by when they got to the scene and was taken into custody.
"My little brother put in a phone call saying 'hey, get over here, there's an emergency - dad just shot somebody'," Daniel Simone, the suspect's stepson, told Action News.
Family members of the suspect tell Action News the suspect shot the 30-year-old victim after the man attacked the suspect's wife.
She and others received medical attention following the incident and were then taken away from the scene for further questioning.
Stay tuned to Action News and ABC30.com for more on this developing story throughout the day.