New Delhi, Dec 30 : The National Investigation Agency (NIA) on Friday arrested four more accused involved in illegal infiltration into India via Tripura, an official said. The official said that the arrests were made in a joint operation with the Tripura Police, as part of the human trafficking case registered by NIA in Guwahati in October, and the arrested accused will be brought to Guwahati after obtaining orders from the court at Agartala for their production before the NIA special court. The NIA had, on November 8, arrested 29 key operatives following nationwide raids on human trafficking syndicates involved in the case. As per NIA investigations, the accused arrested on Friday were located close to the Indo-Bangladesh international border and were linked with the 29 persons arrested earlier. "They had been carrying out human trafficking activities at the behest of racketeers belonging to well-organised syndicates active in several districts of Tripura. The network of syndicates was further connected to operatives based in other parts of India," said a senior NIA official. Investigations have further revealed that the four arrested accused were coordinating with traffickers operating from across the international border to facilitate illegal infiltration of persons of Bangladeshi origin into India. "The NIA had received information about individuals of foreign origin being trafficked illegally with the intention of settling them in various parts of India. The human trafficking syndicates were found to have linkages with other facilitators and traffickers operating in various parts of the country and across the border," said the official. "The linkages were identified as part of a larger network engaged in human trafficking activities via the Indo-Bangladesh border. The accused were also arranging forged Indian identity documents for the individuals trafficked from across the border into India," he added, citing the investigation. /IANS