Kolkata, Feb 19 : The Central Bureau of Investigation (CBI), probing the teachers' recruitment scam in West Bengal, on Sunday arrested Trinamool Congress legislator Manik Bhattacharya's close aide and the president of All Bengal Teachers' Training Achievers' Association, Tapas Mandal, for his alleged involvement in the scam. Niladri Ghosh, an 'agent' in the scam, was also arrested by the CBI on Sunday. In fact, the Enforcement Directorate (ED), which is conducting a parallel probe into the matter, had arrested the secretary of the Trinamool Congress youth wing in West Bengal -- Kuntal Ghosh, on the basis of Tapas Mandal's statements. Manik Bhattacharya, who is the former president of (West Bengal Board of Primary Education WBBPE) is already in judicial custody in connection with the scam. It was learnt that Mondal was summoned to CBI's Nizam police station in central Kolkata on Sunday. After questioning him for three hours, he was arrested. Interacting with the media persons while the CBI sleuths were taking him to a hospital for a medical check-up, Mondal said he did not find any reason behind his arrest. "I was thoroughly cooperating with both the CBI and ED in the course of the investigation. Still, I have been arrested," he said. /IANS