“Four security guards, belonging to a private security agency, have been arrested,” said Annuj Sharma, Special IG of CID.

According to a senior CID officer, the guards — Golam Ambia Sheikh, Sheikh Jahangir, Bapi Sheikh and Abdul Hossain Sheikh — are residents of Burdwan district. The security agency — Inter-tate Security Agency — had started operating a few months ago at Garfa in south Kolkata. The BSNL had hired the security agency to man its exchange offices at Tagore Park on the EM Bypass and G J Khan Road in Tiljala.

According to CID sources, Golam Ambia Sheikh is the kingpin of the racket. The accused used to sell illegal arms at the rate of Rs 35,000 to 40,000.

“The accused used to have fake licences prepared in Nagaland, Bhagalpur and Patna. After forging licences, they purchased firearms from the city and stored them in the BSNL exchange offices,” an officer said.

“The accused were produced in the Alipore court today. As per initial investigation, it seems the four are from the same family. They may have links with Maoists,” an officer said.

The incident has prompted the CID to crack down on private security agencies in Kolkata. “We have information that several of them deal in illegal arms,” said a senior officer.