Police say a 77-year-old man is dead after he tried to break up a fight between his neighbor and his son.
Now his 48-year-old son is held at the Cook County Jail, awaiting court on Tuesday.
Police were called to the suburban Northbrook home in the 1900 block of Thornwood Lane Saturday evening.
That's where police say Donald Christiansen and his son, Ronald M. Christiansen fell down while the elder man tried to pull his son away from a neighbor who his son struck in the face.
According to prosecutors, Ronald and Donald Christiansen lived together at the home on Thornwood Lane.
Police arrested and charged the younger Christiansen with felony aggravated battery, according to the Chicago Tribune. The judge set bail at $25,000 Saturday in court.
His father, Donald Christiansen was pronounced dead at Glenbrook Hospital Saturday night following the fight, according to police and the medical examiner's office. An autopsy was scheduled for Sunday.
The surviving Christiansen has a court appearance Tuesday at the Skokie Courthouse.