Four activists of Dravida Viduthalai Kazhagam, who were arrested by city police following incidents of petrol bomb attacks on the Mylapore and Mandaveli post offices on Tuesday, have been detained under National Security Act.

According to police sources, the mastermind behind the attack Umapathy, his associates Ravanan, Marimuthu and Manohar, were arrested on Wednesday by Mylapore police following the incident. The attacks on Mandaveli post office endangered the lives of residents including women and children residing in the staff quarters above the post office. Following the orders of Commissioner of Police S. George, the four men were booked under the National Security Act on Friday for the attacks on the central government installations. The men are lodged in Puzhal prison.

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