Unable to maintain a mentally ill son, an aged parents ended their life after administering poison to the 32-year-old youth, at Thenur near Madurai on Tuesday night.
The bodies of Kuzhainthaivelu (60), Thangapandiammal (55) and Palpandi (32), have been shifted to Government Rajaji hospital in Madurai for post-mortem.
The Samanayallur Inspector of Police, Krishnakumar, said that the father, who made a living by cutting firewoods, was upset as his son became aggressive in recent times.
He used to beat up his parents and others too ever since he became mentally ill few years back.
The parents gave him a banana laced with some poison and they too consumed the same.
The father has left a suicide note, the Inspector said.