Mohali, Aug. 7 -- The Central Bureau of Investigation (CBI) claimed to have busted an international tech-support fraud and extortion racket operating through fake call centres in Mohali and Delhi, arresting four people, including the alleged kingpin, during raids on Wednesday night.

The syndicate targeted mainly US citizens by posing as representatives of Microsoft, financial institutions and law enforcement agencies, the agency said. The accused allegedly displayed fake pop-up messages on victims' computer screens carrying counterfeit Microsoft toll-free numbers that connected them directly to fraudulent call centres.

The arrested persons have been identified as Sourabh Rana, the alleged kingpin, Indermohan Singh, Harneet Singh and Jap...