Kolkata, Oct 23 : The Central Bureau of Investigation (CBI) informed on Monday that four employees of the regional passport office (RPO) in Kolkata, including three senior passport assistants and one stenographer, have been arrested in connection with the agency's drive against a fake passport racket in West Bengal and Sikkim. Agency insiders told mediapersons that the four person arrested from the Kolkata RPO were produced before a court in Gangtok on October 21, and are currently in CBI custody till October 25. They also said that a total of 24 persons have been named in the FIR filed by the agency, which includes these four persons who have been identified as senior passport assistants Uttam Kumar Bhairon, Nisith Baran Saha and Debasish Bhattacharya, and stenographer Manish Kumar Gupta. Two passport officers and four agents involved in the fake passport racket were earlier arrested by the CBI in this matter. The CBI suspects that the tentacles of this racket might not be restricted within the passport department, but can be spread in other departments of the Union and state governments as well. The agency has already got a lead and uncovered links of an international women trafficking racket behind this scam. The central agency has secured some definite clues about this link following the arrest of a person named Varun Singh Rathor from Naxalbari in Darjeeling district a few days back. The suspicion of the CBI deepened as majority of the fake passports recovered from Rathor were those of women hailing from North Bengal and adjacent Sikkim. /IANS