A 74-year-old man, Narasimha Marakala, residing in Gopadi, Koteshwara, was murdered by his son on Saturday night.
The accused, identified as Raghavendra Tolar, alleged that his elderly father frequently threatened to murder him.
On Saturday around 10.45 pm, he attacked his father with a sickle when the former objected to setting the dry grass and other waste in the compound on fire.
The daughter, Sujatha, and her husband who came to the rescue of Narasimha were also assaulted by Raghavendra.
The police have taken the accused in custody. A case was registered in the Kundapura police station.