Kolkata, Oct 12 : Enforcement Directorate (ED) has started investigation into the alleged irregularities in the rationing distribution system in West Bengal. A team of ED sleuths, escorted by armed personnel of central armed police forces, conducted marathon raid and search operations at the residence of businessman Bakibur Rahman, known to be close to a politically influential person in the state. It is learnt that one team of ED sleuths reached the residence of Rahman at a posh housing complex at Kaikhali in the northern outskirts of Kolkata. The second team of the central agency sleuths conducted raids and search operations at a hotel owned by Rahman. A third team of ED sleuths conducted parallel raid and search operations at the residence of a business associate at Rahman whose name is Abhishek Biswas. Besides conducting the raid and search operations, the central agency also questioned Rahman and Biswas. Sources said that recently the ED sleuths got access to certain documents regarding the operations of a rice-mill owned by Rahman, which hinted towards a major irregularity in the rationing distribution system in the state. It is learnt that ED started its probe in the ration distribution irregularities from Wednesday when their sleuths went to certain rice-mills in the districts and questioned the owners of these mills. /IANS