Kolkata, Jan 5 : National Investigation Agency (NIA) on Friday conducted raid and search operations at an office of State Food & Supplies Department at Gaighata in North 24 Parganas district of West Bengal regarding nationwide probe on human trafficking. Sources said that the raids were follow-up actions of an arrest made by the central agency from Gaighata area in November last year. On November 8, the NIA arrested Bikash Haldar from his rented accommodation at Anandapur area in Gaighata in connection with human trafficking. NIA had also seized documents from Haldar's residence. NIA investigation has revealed that Haldar -- who used to stay at that rented accommodation in Gaighata with his wife and daughter -- are actually residents of Bangladesh. As per statements given by Haldar's wife to NIA, the family had come to West Bengal for treatment and in the interim period their visas expired, following which they were unable to go back to Bangladesh. NIA also raided the residence of a local businessman in Barasat in North 24 Parganas district were it recovered documents. Sources said that the NIA's raid at the State Food & Supplies Department was probably linked to the documents seized by the central agency. On Friday, a team of ED and CAFP was also attacked by the local people when they had attempted to raid TMC leader Sheikh Sajahan's residence in Sandeshkhali area. /IANS