After a credit card fraud involving two Convergys employees rocked the city, another scam has surfaced at the Gurgaon branch of WNS, a leading global business process outsourcing firm. The firm filed a fraud case against its three trainees in September last year. Gagandeep Singh, a 27-year-old trainee, has been named the main accused. His colleagues Sumit Singh Tomar, 26, and Tanmay Gautam, 22, are the other two named in the case. Gagandeep is believed to have left the country.