According to police, Santhosh (25) and his mother Komathyammal (52), surrendered last night in connection with the case.
The man had shot his father Palanisamy (56) dead following an altercation over division of property at the latter's house in Vasuvapatty village in the district. He also shot his grandmother, police said.
Santhosh had got into a wordy duel with his father and demanded immediate transfer of all the property belonging to Palanisamy as he was the legal heir, police said adding this led to the murder.
The two were arrested and the car used by Santhosh was also seized.