Iyappan, 30, of Karakkottai near Mannargudi was arrested on charges of murdering his grandparents.

According to the police, Iyappan was living with his mother Devi, 50, after his father Kaliyaperumal, 55, who works in Malaysia, got separated from her. Iyappan, who had undergone rehabilitation for drug abuse at private homes in Tiruchi and Puducherry and the Government Medical College and Hospital, Tiruvarur, remained in touch with his father.

Two days ago, the accused visited his grandparents, Pitchaimuthu, 72, and Chandra, 66, who lived in the same village.

As they refused, he attacked and inflicted bleeding injuries on them. As the senior citizens swooned, the accused went to a nearby fuel pump station and bought a few litres of inflammable liquid. He poured it on his grandparents and set fire. Later, he went to his residence and informed his mother about the crime.

Meanwhile, on hearing about the crime, Mannargudi police visited the spot and shifted the bodies to the Government District Headquarters Hospital at Mannargudi for postmortem. The accused was arrested and is being interrogated, the police added.