The couple -- Krishnasamy and Mahalakshmi -- beat their son with a hammer and an iron rod resulting in his death in their house near Sulur on the city outskirts after he started attacking them without any reason soon after getting up early in the morning, police said adding, the two had been arrested.
Rajendran, who developed some mental disorder a few months ago, started behaving abnormally and used to attack his wife and 9-year old son, without any provocation, police said.
Though the parents got him treated at a hospital, his condition did not improve.