Unable to bear the “torture” from their mentally disturbed son, parents today hammered him to death in their house near Sulur, about 25 km from here.

Rajendran, 41, suddenly developed some mental disorder and his behaviour turned abnormal. He started attacking his wife and 9-year old son, without any provocation, since the past few months, police said.

So his wife left the house with the son and Rajendran was staying with his parents – Krishnasamy and Mahalakshmi in Kangeyampalayam.

Noticing the abnormal behaviour, neighbours and passersby blamed the parents, who then took Rajendran for treatment. But there was no improvement.

Rajendran, who woke up early today, started beating his parents, without any reason. Unable to bear this, the parents took a hammer and an iron rod and started beating him, which resulted in his death, police said.

Police rushed to the spot, recovered the body and arrested the parents.