The Maharashtra Anti Terrorism Squad (ATS) has invoked the stringent provisions of Maharashtra Control of Organised Crime Act (MCOCA) against the four arrested accused in the 13/7 Mumbai triple blasts case.Three blasts had taken place within minutes of each other at Zaveri Bazaar, Opera House and Dadar on July 13 last year killing 27 persons and injuring several others. According to the ATS, the blasts were allegedly carried out by terror outfit Indian Mujahideen, in which its top operative Yasin Bhatkal was directly involved. Bhatkal is still absconding while other accused Naquee Ahmed, Nadeem Sheikh, Kanwar Pathrija and Haroon Naik were arrested and are currently in judicial custody.According to the agency, one of the accused Nadeem Sheikh has, in a confessional statement recorded by a magistrate, admitted to the alleged offence.